♪♪ ♪♪ ♪♪ ♪♪ -Today on "America's Test Kitchen," Lan makes Julia a showstopping ice cream cake, and Dan reveals the unexpected cooling powers of melting ice.

It's all coming up right here on "America's Test Kitchen."

"America's Test Kitchen" is brought to you by the following.

-Plugrà European style butter was created for all chefs, cooks, and bakers, slow-churned with 82% butterfat for a smooth texture and more pliability for flaky crusts.

Plugrà -- from professional kitchens to your home.

-Smithey cast-iron and carbon-steel cookware -- thoughtfully crafted, made with passion, used with passion.

Welcome to the world of Smithey.

-On an American Cruise Lines journey, travelers experience the maritime heritage and culture of the Maine coast and New England islands.

Our fleet of small cruise ships explore American landscapes, seaside villages, and historic harbors where you can experience local customs and cuisine.

American Cruise Lines, proud sponsor of "America's Test Kitchen."

-GreenPan Frost, the frozen treat maker that makes ice cream, sorbet, slushies, and more with a built-in chiller that goes from fresh to frozen.

GreenPan Frost.

♪♪ -I've eaten ice cream cake my entire life because it's my signature birthday cake, and it's always been roughly the same with a layer or two of ice cream separated with chocolate cookie crumbles.

But today, Lan's going to show me a new kind of ice cream cake that actually includes a layer of actual cake.

-Cake in ice cream cake.

It's shocking.

-[ Laughs ] Mind blown.

-I worked at a restaurant where whenever it was someone's birthday -- front of the house, back of the house, didn't matter -- my job was to run to the ice cream shop next door to pick up an ice cream cake for staff meal, and that was where I got to try this.

When I was assigned this recipe, I went straight to the ice cream shop to talk to Gus and Mimi Rancatore, who run Toscanini's -- -Ah.

-...to learn how they make their ice cream cakes.

So that's what I'm going to show you.

-Okay.

-So I know we've talked about cake and ice cream.

-Mm-hmm.

-We're starting with fudge sauce.

-[ Both chuckle ] It's going to be the thing that brings those two layers together.

Um, and it's really easy.

So we're going to start with 7 tablespoons of unsalted butter.

I've got it in a small pot here.

And it's cut up into little chunks so it melts faster.

To that I'm adding 1/3 of a cup of milk.

So I've got a cup of sugar here.

It's going to go right in.

And we're going to heat this gently over medium low heat.

And all I'm looking for here is the butter to melt and that sugar to start dissolving.

It's going to take maybe 3 minutes.

-Okay.

-So while you keep an eye on that, I'm going to get to the chocolatey bits.

So this is 1/2 a cup of cocoa powder unsweetened because we want to control the sugar.

Next up is some heavy cream.

This is 1/3 of a cup.

Finally, a little bit more sugar.

I think it's really important to withhold some of the sugar from the pot.

And you're going to see why in a minute.

This is 1/4 cup.

Last up, this is 1/4 teaspoon of table salt.

So the reason I'm withholding some of the sugar is I'm going to use it to break up those clumps of cocoa powder instead of sifting, which I find annoying.

It just gets everywhere.

And we're just looking to make a nice thick paste.

Okay.

So everything's well combined.

And now that our butter is melted and it's already looking like some of that sugar is dissolved, you can see there's some translucency here.

-Mm-hmm.

-All of this goes right in.

We're going to give this a whisk.

And this is going to cook.

And it's already taking on that sheen that you want.

-Mmm.

-So I want to turn the heat down to low while I do this.

And the reason for that is I don't want to evaporate too much water.

If we lose too much water, it's going to be too hard.

-Makes sense.

-So this is just going to cook for about 5 minutes.

And what you'll see, if you're really paying attention, is it'll thicken up slightly, The starches in that cocoa powder, they're going to cook and hydrate and absorb some of the water and it'll thicken the sauce.

Okay, Julia, it's been about 5 minutes.

We're still at a gentle simmer, and it's time to get the rest of the ingredients.

-Bring me a straw.

It looks delicious.

-[ Laughs ] So next up, I've got 2 1/2 ounces of finely chopped unsweetened chocolate.

-Okay.

-And again, we're trying to control the amount of sugar that's going in here, so that's why unsweetened.

And then finally a teaspoon of vanilla extract.

So I want to shut off the heat.

This last step we're just whisking to make sure all of that chocolate is melted and evenly distributed.

Looks great.

-Looks perfect.

-Let's get it into a bowl and let it cool.

-Oh, look at that.

-So this needs to cool fully before we can use it.

That takes about an hour and a quarter.

-But you could obviously make this in advance, if you were planning to make this for someone's birthday.

-That's absolutely right.

This will keep in the fridge for about a week, and you just need to let it come back to room temperature before you can use it.

Alright, Julia, it's time to make this cake I've been talking about.

I've got a 9-inch springform pan here, and we're going to use this for both baking the cake and assembling and stacking that ice cream cake.

-Very clever.

-Step one, I've got a little baking spray and I'm just going to spray the bottom.

I'm not going to put it together first.

And this is just going to provide a little bit of glue to help our parchment stay in place.

And that'll make unmolding this cake a little bit easier.

Pop the collar on.

Alright, Julia, time for the cake.

-Mm-hmm.

-I've got 2/3 of a cup of cake flour here.

And to that, I'm adding 6 tablespoons of sugar.

Now, this is a tiny bit more sugar than you would normally see in a cake.

Um, but because it's frozen, you're not going to taste that sweetness.

The sugar will keep the cake from being too firm even though it's cold.

-Okay.

the other ingredients are 1/2 a teaspoon of baking powder and 1/8 of a teaspoon of table salt.

In the end, it's about getting enough sugar in there to prevent the water in the cake from turning into ice.

It depresses the freezing point just enough.

-Okay.

-So we whisk our dry ingredients together.

No more lumps.

And then we can add most of our wet ingredients.

I've got one large egg.

Two large egg yolks.

And we've saved those whites.

Don't worry, I'm not wasting anything.

This is 3 tablespoons of vegetable oil.

This is going to help tenderize the cake.

2 tablespoons of water.

-Oh, interesting.

-Yeah.

There's definitely more water in here than you would normally see.

And then last up, a teaspoon of vanilla extract.

And we'll just whisk this together until it forms a nice smooth batter.

Okay.

That's it.

Making ice cream cake is -- it's a project.

So I wanted to keep all the steps as simple as possible.

Alright.

Next up, those egg whites I was talking about.

Now we're going to use them.

They're not only full of water, they're full of protein.

And protein will provide the structure for this cake.

And then just a pinch of cream of tartar.

Just throw that right in.

And broke out the hand mixer for you.

-Old school.

-Yeah, I haven't used one of these for so long, but there's so little stuff in here, you can't really use a stand mixer.

So I'm going to beat this at medium low speed until it's nice and foamy.

It's going to take about 30, 60 seconds.

[ Hand mixer whirring ] That's looking pretty good to me.

Nice and broken up.

There's no stringy bits.

So next, I'm going to sprinkle in 2 tablespoons of sugar.

And this sugar is just going to help these egg whites beat up to stiff peaks and hold those peaks.

So I'm going to beat this until stiff peaks form.

That'll take 1 to 2 minutes.

And we can crank it up this time.

[ Hand mixer whirring ] Alright.

What do you think?

-I think you're good.

Let's see.

Look at that.

-Yeah.

-Perfect.

-So I'm going to scrape about 1/3 of this into that batter.

And we're just going to whisk it.

We're not trying to preserve the bubbles.

What we do want to do is lighten this and make that less thick and viscous, so that when we fold this in, those bubbles stick around.

-You're tempering it.

-Yeah.

Exactly.

You just want them to have a similar consistency before you start folding.

Um, and it's totally okay that it's a little streaky.

So the rest of these egg whites can go right in.

And then we're just going to fold.

We're almost there.

I can still see a couple streaks of white.

Alright.

Let's get this in that pan.

We're going to bake this in a 300-degree oven on the middle rack.

It's going to take 20 to 25 minutes.

It's not going to pick up much color.

It won't look like the most beautiful cake.

Then we're going to top it with fudge and ice cream.

-I can smell it.

-Yeah.

It's just kind of a light vanilla cake.

Really simple.

Really elegant.

-You're right.

That doesn't look like much.

-It doesn't.

That's okay, though.

It's -- It's -- It's structural.

You can see there's a tiny bit of browning around the edges.

The top is a little bubbly.

-Mm-hmm.

-Sometimes it comes up a little more bubbly and, like, totally fine, don't stress it.

-Okay.

-You can see it's slightly domed.

-Mm-hmm.

-Now, normally we would let this cool slightly, run a knife around it, and get it out of the pan so we could cool fully.

-Mm-hmm.

-We're not going to do that this time.

-What are we going to do?

-We're going to let it cool in the pan.

And the reason for that is I want this cake to stay stuck to the pan through the entire cooling process.

-Okay.

-Those egg white proteins that are forming the structure for this cake, um, they're going to contract and shrink as the cake cools.

And if you unmold that cake, those sides go from something like this...to that.

So the solution is really simple.

We're going to let this hang out for about 45 minutes until it's fully cooled before we can take it out.

Julia, it's been 45 minutes.

-Mm-hmm.

-You can see the cake has collapsed slightly.

-Yeah.

-Yeah.

So I'm just going to run a knife around the perimeter to release it.

-Looks loose.

-Moment of truth.

-Ta da!

[ Chuckles ] I felt like it needed a presentation moment.

-So what we want to do is get it off this pan and get that parchment off of there.

I'm just going to invert it.

Lift off our parchment because no one wants a bite of that.

And then I'll reinvert.

Just because the amount of sugar we have in this cake can grab water as it cools and that surface gets super sticky, this will make getting the cake off of the rack a lot easier.

Julia, it's time to stack that cake.

We're going to use the same 9-inch springform we used to bake, because it's the right size.

-Mm-hmm.

-And there's just a little bit of prep you got to do.

Um, a lot of recipes will have you unmold the cake by warming it, but that melts the ice cream.

Not ideal.

I think it's a lot easier to line the pan with parchment.

But if you just put parchment in there, it's kind of all over the place.

It makes assembly tough.

-Mm-hmm.

-So what I do is I take all that parchment out, give it a quick spray, and then line the pan.

It goes in the freezer just to chill so that our cold ice cream isn't hitting a warm pan.

And at the same time, the ice cream in the freezer goes to the fridge to temper.

It's going to take about 20 minutes to warm up to -- to a workable consistency.

-Okay.

-I've got a prepared pan and tempered ice cream ready to go.

I'm just going to go get it.

-Okay.

-So here's our nice and chilled pan.

I've got 3 quarts of ice cream here.

I hope you like pistachio.

-I love pistachio.

-Oh, good.

Oh, good.

Because that's what I'm making.

-[ Laughs ] -Um, this is nice and tempered.

It should be soft.

Nice and soft to the touch.

Very scoopable.

So now that the ice cream is out, we're kind of on a little bit of a timeline.

I don't want this to melt.

And so I'm going to work fairly quickly.

I want to scoop about 1/4 of this into the pan.

And then just for fun, I thought it would be nice to add a ripple.

And I'm going with apricot.

It'll add a nice brightness and acidity.

You can use up to a cup of any inclusion.

It can be preserves.

You could buy some lemon curd.

You could chop up brownies or cookies or cake.

Candy.

It's really -- It's kind of up to you what you want to do.

Do you want to get more of that?

-Oh, you bet.

-I'm not really worried about getting things in evenly.

It's actually kind of nice to have it be a little bit haphazard.

-Oh, okay.

-A slice, the cross-section is just beautiful.

So ice cream's in.

Now we need to make it into an even layer.

And the way to do that without melting things with our hot little hands is this little setup I have.

First, I want some plastic wrap down so that I'm not mushing directly onto ice cream.

Gluing the parchment strips to the pan is really helpful.

-Mm-hmm.

-It's not moving around.

And then I want to use a kitchen towel just because it'll insulate the ice cream from my hands and prevent things from melting.

And there's really no right way to do this.

All I'm trying to do is flatten this into a mostly even layer.

So mostly flat parchment is still in place.

We'll peel off this plastic wrap.

And here's where our chocolate sauce is critical.

-Oh, yes.

-Um, because that layer isn't perfectly smooth, if I were to pop the cake on right now, there'd be kind of gaps, right?

-Mm-hmm.

-This fudge sauce, it's going to even everything out.

So that is 3/4 of a cup of that fudge sauce.

I've just warmed it slightly, so it's spreadable.

So last up is our cake layer.

Um, it's really nice to build this thing upside down.

You just kind of slip it in.

-Oh, look at that.

It's a flat top.

-It is.

It's...like you did a perfect job baking it.

And then we're just going to give this a nice little press just to flatten it out and make sure there's no air in there.

And then if you could hand me a piece of plastic wrap, we'll just wrap this up and pop it in the freezer to set.

I like to do this just to keep the cake from absorbing weird smells in the freezer.

♪♪ -I've got a math problem for you.

I have 2 ounces of whiskey at 70 degrees, and I have a cup of ice which is at 32 degrees.

What temperature will they be after 30 seconds of shaking?

You might guess 40 degrees, maybe even 32.

Well, let's find out.

[ Ice rattling ] -Okay.

We're at 40 degrees.

Actually, under.

34 degrees, 32 degrees.

But it keeps going.

And stop.

20 degrees.

That's 12 degrees colder than the ice we started with.

How is that possible?

Well, ice cools in two ways.

The first is pretty obvious.

It is colder than the whiskey, so it removes heat and the temperature drops.

But ice is much more powerful at cooling because it melts.

Melting is a phase change, and it takes a ton of energy for water to change from one phase to another.

In our drink, that additional energy is pulled out of the liquor in the form of heat, chilling well below the initial temperature of the ice.

So the next time you make a drink and you take that first super cold sip, may I suggest that you make a toast to phase changes?

Your friends won't like it, but I will.

♪♪ -Julia, I've got a nice and chilled bowl and chilled beaters.

And what we're going to make is a whipped cream frosting.

-Great.

-So this is 1 1/2 cups of heavy cream.

Um, and again, nice chilled bowl to make whipping easier.

I'm going to sweeten it lightly with 2 tablespoons of sugar, and then last up, just for an extra bit of flavor, vanilla -- 1 teaspoon.

I want to start slowly so that I'm not splashing you with heavy cream.

-[ Laughs ] -This is looking nice and thick.

-Mmm, mmm.

-And I'm going to go up a little bit faster.

Um, the reason I don't want to go with medium peaks here is I want as much air in there as possible.

This cream is going to be the insulator, and it's going to keep our ice cream cake from melting.

And so the more air there is in there, the better it'll be for that job.

That's looking pretty good.

-Looks good.

-Alright, so I'm going to need about 2/3 of this to mask that cake to coat it fully.

The rest is going to be for decorating.

In order to mask this cake quickly, we're actually going to use a piping bag.

I've fitted it with a 1/2-inch petal tip.

You can see how it's flat.

And that's going to help us apply that whipped cream quickly and evenly.

So 2/3 of this is going to go in the bag.

Okay.

This will hang out here.

This I'm going to pop in the fridge so that it holds its shape while we're working on the cake.

Julia, here's our cake.

Now, I chilled this for 4 hours to ensure that the ice cream has fully set.

-Mm-hmm.

-But of course, you could do this a couple of days in advance if you wanted to.

So we're just going to remove this collar.

And then look at how easy this is.

You just peel the paper away.

There's no fussing with trying to, like, warm the sides to get it out of a pan.

-Mm-hmm.

-Now you can build this on a platter or a cake stand.

I like to make sure I have something really flat.

So the other thing I did was I chilled this cake stand.

It's just going to buy us a little bit more time for decorating.

-Very smart.

-I want to get this off.

I usually just spin it gently and ease the sides of the pan from the cake.

And you can see it's starting to lift slightly.

And once it does, I use an offset to kind of... Oh, you know what?

This one's coming off beautifully.

-Ta da!

-Doesn't this look fun already?

-Yes.

-It's only going to get better from here.

Okay, so this is great, but it's going to melt if we don't cover it with some insulation, which is what the whipped cream frosting is.

-Gotcha.

-I'm going to set it on a turntable, because that'll make applying the frosting a lot easier.

Do not stress doing it neatly.

-Okay.

-You just want to get it on there.

So you can see you just kind of squeeze gently and rotate the pan, and as you work your way up, if there are gaps, that's actually kind of good.

Those gaps in between, it's going to keep the whipped cream from freezing solid immediately.

That'll mean that there's time for us to even it out.

We're just going to smooth everything into place.

That's looking pretty good, right?

-It's looking great.

-I don't really stress it if it doesn't look perfect because it's a really thin layer of frosting.

And we're going to actually add some decor that will kind of hide any imperfections.

So now that the frosting is on, we're going to pop this back in the freezer and let it set.

It's going to take about 20 minutes to set up, and the way to check for that is you kind of feel the whipped cream at the very bottom where the cake meets the plate is the last to solidify.

-Okay.

-So this cake is now fully set.

And what's really nice about it, it's firm, right?

-Oh, yeah.

Very firm.

-What's really nice is at this point, you don't have to rush.

If you want to do some fancy decorating, you can absolutely go to.

-How long can this hang out while you decorate it?

-I've had it out for about... I'd call it half an hour and not had trouble with the ice cream melting or it losing its shape or anything.

-Interesting.

-It's, um, there's so much mass in there that's really cold that, um -- -Mm-hmm.

-...it just gives you more freedom to take your time, which is, you know, the decorating part is -- -This is the fun part.

-Yeah.

It's great.

So I'm going to keep this pretty simple.

I'm just going to pipe a ring of dots around the top.

-Awe.

-Now, I promised you that not doing a perfect job on the sides wouldn't matter.

Here's why.

Um, you can actually press candies, cookies, crumbs, whatever you have that you feel like using.

Um, I'm going to use sprinkles.

-Oh.

-Depending on the size and shape of the pieces, you're going to need anywhere between 2/3 to 1 cup of decor, and I like to pop it in a big pan that'll catch any of the bits that kind of come bouncing off.

-Mm-hmm.

-And this is going to feel a little dangerous, but it's -- it's pretty easy.

Um, I just want to pick up a handful in my hands, and I'm just going to press them onto the sides of the cake.

And I'm not going to stress making sure that it's perfectly uniform.

And just kind of rotate and press.

It really does hide any flaws, and it adds a nice bit of texture on top.

I'm just going to take a second to clean up this plate.

But before I do, top's looking a little plain, right?

-Awe, that looks so sweet.

-Now I know it looks like it's ready to go.

-It does.

-Almost.

I'm going to pop this in the freezer to make sure that everything is fully set, and it can hang in the freezer for 1 hour to 24 hours.

-Okay.

-Julia.

Half an hour ago, I moved this cake from the freezer to the fridge, and there it came up slowly so that we have a better texture for serving and slicing.

-That makes sense.

Not a hard freeze any longer.

-Correct.

Are you ready for this reveal?

-Yes.

-Okay.

-Who goes small with ice cream cake?

-I'm not judging.

[ Laughs ] -I am judging.

[ Laughs ] Go big or go back and get seconds.

[ Both laugh ] -Yeah, yeah, that's exactly it.

-Oh.

Oh-ho-ho.

-What do we think?

Not bad, right?

-Oh, that's gorgeous looking.

The whipped cream on top almost has a little shimmer sprinkled to it.

It almost looks like frosted or snow, you know.

-Yeah.

Yeah.

-And that's the neat thing that happens when whipped cream freezes.

It's got a natural glisten.

-Yes, it's just extra festive.

-Yeah, I know what that is.

That's the extra chocolate sauce you made.

-It is.

I just warmed it gently in the microwave, 50% power, just till it was nice and saucy.

I'm going to make sure to get it on the side of the cake so that it doesn't melt everything.

-Mmm.

That's delicious.

[ Chuckles ] -Mm-hmm.

-The cake has the perfect texture.

It's almost like the middle of a macaron.

Just a little chewy.

Your teeth go right through.

It's satisfying.

Oh, and that fudge.

-It's so satisfying.

-Mmm.

-And the really awesome thing is, even though I've cut into it, this cake, I've had it out cut for about half an hour and it barely melts.

-Really?

-Yeah, it's -- it's just so easy to serve.

-I really appreciate that cake on the bottom.

It gives a texture you don't usually get.

It gives you that chewy texture -- -Mm-hmm.

-...that you've always kind of wanted in ice cream cake.

And it's not just melting.

Lan, this is spectacular.

This is the best ice cream cake I've ever had, hands down.

And I've eaten -- I've eaten 50 years of ice cream cakes, so I know what I'm talking about.

[ Laughs ] If you want to make this incredible ice cream cake, don't grease the sides of the pan when making the chiffon cake layer.

Assemble the layers of ice cream, fudge, and cake into the springform pan upside down, and cover the cake with a base layer of whipped cream and chill it well before decorating.

From "America's Test kitchen," hands down the best ice cream cake.

This is incredible.

I'm surprised testing went on so long that you -- [ Laughs ] -Are you really now?

-No.

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-Plugrà European style butter was created for all chefs, cooks, and bakers, slow-churned with 82% butterfat for a smooth texture and more pliability for flaky crusts.

Plugrà -- from professional kitchens to your home.

-Smithey cast-iron and carbon-steel cookware -- thoughtfully crafted, made with passion, used with passion.

Welcome to the world of Smithey.

-On an American Cruise Lines journey, travelers experience the maritime heritage and culture of the Maine coast and New England islands.

Our fleet of small cruise ships explore American landscapes, seaside villages, and historic harbors where you can experience local customs and cuisine.

American Cruise Lines, proud sponsor of "America's Test Kitchen."

-GreenPan Frost, the frozen treat maker that makes ice cream, sorbet, slushies, and more with a built-in chiller that goes from fresh to frozen.

GreenPan Frost.

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