Tiramisu Ice Cream Cake

1 . Stage

Prepare cake: Preheat the oven to 350 degrees F (175 degrees C). Butter a 9-inch square baking pan. Line the pan with parchment paper and butter again. Flour pan and set aside.

2 . Stage

Sift flour and cornstarch together in a small bowl. Combine egg yolks, 1/2 cup sugar, and vanilla in the bowl of a stand mixer fitted with the whisk attachment; beat on high speed until thick and pale, about 5 minutes. Transfer to a large bowl.

3 . Stage

Wash and dry the mixer bowl and whisk and return to the stand. Combine egg whites and salt in the bowl; beat on medium speed until whites hold soft peaks, 1 1/2 minutes. Slowly add the remaining 1/4 cup sugar while the mixer is running. Continue beating until stiff and glossy, about 1 minute. Fold the egg white mixture into the egg yolk mixture. Fold in the flour-cornstarch mixture in 3 batches. Transfer batter to the prepared pan and smooth the top with an offset spatula.

4 . Stage

Bake in the preheated oven until a cake tester inserted in the middle comes out clean, 35 to 40 minutes. Cool on a wire rack for 5 minutes. Run a table knife around the edges to loosen. Invert carefully onto a serving plate or cooling rack. Let cool completely, about 30 minutes.

5 . Stage

While the cake is cooling, prepare syrup: Combine sugar and water in a small saucepan over medium heat; bring to a boil, stirring occasionally. Remove from the heat and stir in espresso and coffee-flavored liqueur. Set aside to cool.

6 . Stage

Prepare ice cream layer: Use a serrated knife to cut cooled cake in half horizontally, making 2 layers. Place one layer in the bottom of a 9-inch square baking pan. Brush the top with 3/4 cup cooled syrup, then sift 2 tablespoons ground espresso over top.

7 . Stage

Place espresso ice cream in the bowl of a stand mixer fitted with the paddle attachment. Beat on low speed until ice cream is spreadable. Spread ice cream over cake, then top with second layer of cake. Brush with remaining syrup and place cake in the freezer for 20 minutes.

8 . Stage

Remove cake from the freezer and sift remaining espresso over top.

9 . Stage

Place coffee ice cream in the bowl of a stand mixer fitted with the paddle attachment. Beat on low speed until ice cream is spreadable. Spread ice cream over cake, forming large swirls. Return to the freezer and freeze until completely hard, at least 2 hours.

10 . Stage

To serve, garnish with chocolate curls.