Ice Cream Cake with Pretzels, Fudge, and Salted Caramel
This cake is a labor of love. No part is especially difficult to prepare, but with all of the assembling and freezing, the time adds up. Do not skimp on the freezing time, though; a melty, muddled cake isn't worth it.
I saw Alison Roman’s recipe for a Banana Split Ice Cream Cake in Bon Appetit when it came out last summer and I’ve been in the mood for a good, big, celebratory ice cream cake ever since. This one fits the bill, with its 10 layers standing over 6 inches tall. I made it over the course of three days, but if you’re more organized than I am (and don’t, say, get distracted and let it rest for 20 hours in between layers 4 and 5), you can do it in two.
Regarding special supplies, I couldn't find clear acetate anywhere. In place of it, I bought some cheap flexible plastic signs from the hardware store, washed them well, and taped them together. It worked just fine in a pinch, but if you plan ahead, you can buy acetate online.
Adjustments: Use chocolate ice cream instead of vanilla; swap the pretzels and peanuts out for mini marshmallows and chocolate chips, or crushed up candy bars (Kit Kat/Snickers/Take5/Heath Bar), or crumbled up chocolate chip cookies; buy already-exciting ice cream instead of “making" your own (think Ben & Jerry’s, Jeni’s, Izzy’s!)
1 cup/120 grams all-purpose flour
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon kosher salt
1/2 cup plus 1 tablespoon/48 grams unsweetened cocoa powder
1/2 cup/120 milliliters hot water
4 tablespoons/57 grams unsalted butter, at room temperature
1 cup/213 grams very firmly packed dark brown sugar
1 large egg plus 1 large egg yolk
1/2 cup/120 milliliters buttermilk
1/2 teaspoon pure vanilla extract
Chocolate cookie crumble
2 9-ounce packages chocolate wafer cookies*
1 cup/200 grams virgin coconut oil, melted
1/4 teaspoon kosher salt
1 cup/240 milliliters heavy cream
6 tablespoons/80 grams brown sugar
4 1/2 tablespoons/25 grams cocoa powder
1/4 cup plus 2 tablespoons/117 grams corn syrup**
9 ounces bittersweet chocolate, coarsely chopped
1 1/2 tablespoons/21 grams unsalted butter
1/2 teaspoon kosher salt
2 cups/400 grams sugar
1/2 cup/113 grams butter
1/2 cup plus 2 tablespoons/150 milliliters heavy cream
1 1/2 cups/360 milliliters heavy cream, chilled
3 tablespoons/37 grams sugar
1 cup/240 milliliters heavy cream
8 ounces bittersweet chocolate, coarsely chopped
6 pints vanilla ice cream, divided
4 cups pretzels, crushed, divided
1 cup peanuts, coarsely chopped, divided
Special equipment: candy thermometer, clear acetate
Make devil's food cake
Preheat the oven to 350°. Spray a 10-inch springform pan with nonstick cooking spray. In a medium bowl, whisk the flour with the baking powder, baking soda and salt. In a small bowl, whisk the cocoa powder with the water until a smooth paste forms. In the bowl of a stand mixer fitted with the paddle, beat the butter with the brown sugar at moderate speed for 3 minutes. Beat in the egg, egg yolk, buttermilk and vanilla. At low speed, beat in the dry ingredients and cocoa paste in 2 alternating batches.
Scrape the batter into the prepared pan and bake for 30 to 35 minutes, until a toothpick inserted in the center comes out with a few moist crumbs attached. Let the cake cool for 15 minutes, then remove the ring and let the cake cool completely on a rack. Once cake is cool, level with a serrated knife.
Make chocolate-cookie crumble
Pulse cookies in a food processor until coarsely ground. Transfer to a large bowl and add coconut oil and salt. Mix with your hands until crumbs are coated in oil and mixture resembles wet sand.
Spread out crumbs on a parchment-lined rimmed baking sheet in an even layer (do not press). Freeze crumbs on baking sheet 30 minutes, then crumble into very small pieces with your hands. Freeze until ready to use.
Make hot fudge
In a small saucepan, combine the cream with the brown sugar, cocoa powder and corn syrup and bring to a boil over moderate heat, whisking constantly. Reduce the heat to low and simmer for 1 minute. Remove from the heat and add the chocolate, butter and salt; whisk until smooth. Scrape the hot fudge into a bowl and let cool to room temperature.
Place the sugar in a large saucepan with 50ml of water, and gently heat over a low heat, swirling the pan but not stirring, until just melted. Turn up the heat a little and simmer gently, swirling regularly, until you have a clear, very dark golden caramel. Cube the butter. Remove the pan from the heat, then carefully and quickly whisk in the butter and cream. It will splutter a bit, but don’t worry about that. Keep whisking and beating until smooth, then beat in the ½ teaspoon of sea salt.
Let it cool. If making the caramel in advance, keep it chilled but bring back to room temperature before using.
In the bowl of a stand mixer fitted with the whisk, beat heavy cream with the granulated sugar until it holds soft peaks. Refrigerate until ready to use.
Place the chocolate in a heatproof medium bowl. In a small saucepan, bring the remaining 1 cup of heavy cream to a boil. Pour the hot cream over the chocolate and let stand until melted, about 5 minutes. Stir until smooth, then tap the bowl on the counter to pop any air bubbles. Let the ganache cool down to 80°, about 30 minutes.
Place cake in springform pan. Using scissors, trim a sheet of clear acetate to 7-by-24 inches. Wrap the acetate around the inside of the springform pan, around the cake, and secure it with tape.
Using an offset spatula, spread half of the hot fudge evenly over the cake and top with half of the cookie crumble. Freeze until the fudge is firm, about 20 minutes. 2 cups cookie crumble
A few minutes before the 20 minutes is up, prepare ice cream 1: Mix 2 pints ice cream in a large bowl with a wooden spoon until it resembles thick cake batter (it should be soft but not melted). Fold in 1½ cups cookie crumble with a rubber spatula.
Remove cake from freezer and scrape ice cream into pan; smooth top. Sprinkle 1 cup cookie crumble over ice cream, pressing lightly to adhere. Spread second half of the hot fudge evenly over the cookie crumble. Freeze until the fudge is firm, about 20 minutes.
A few minutes before the 20 minutes is up, prepare ice cream 2: Mix 2 pints ice cream in a large bowl with a wooden spoon. Fold in 1 1/2 cups crushed pretzels and 1/2 cup peanuts with a rubber spatula.
Remove cake from freezer and scrape ice cream into pan; smooth top. Top with remaining cookie crumble, pressing lightly to adhere. Freeze 20 minutes.
Remove cake from freezer and scrape salted caramel into pan; smooth top. Freeze 20 minutes or until firm.
A few minutes before the freezing is up, prepare ice cream 3: Mix 2 pints ice cream in a large bowl with a wooden spoon. Fold in 1 1/2 cups crushed pretzels and 1/2 cup peanuts with a rubber spatula.
Remove cake from freezer and scrape ice cream into pan, smoothing top. Freeze 20 minutes, or until firm.
Spread whipped cream over ice cream layer 3. Freeze cake overnight.
Remove cake from freezer. Carefully remove the springform ring and peel the acetate off the cake. Transfer the cake to a rack set over a rimmed baking sheet. Working quickly, pour the ganache onto the center of the cake in one fluid motion, allowing the excess to drip over the side. Freeze the cake until the ganache is firm (at least 2 hours before serving).
Slice with a clean, warm knife.
Make ahead: Cake keeps in the freezer for up to a week.
*For the life of me, I couldn’t find standard chocolate wafer cookies. In place of them, I used 8 ounces of chocolate wafers and 10 ounces of chocolate teddy grahams. You could also use oreos, but I’d then cut the coconut oil in half.
**If you don’t have a kitchen scale, coat your measuring spoon with flour before measuring the corn syrup. The flour acts like non-stick and the corn syrup will come right out, no sticky spatulas or fingers needed.