Triple Chocolate Mousse Cake

Pin It

I've been wanting to make this cake for a long time now- ever since I saw it featured in one of ATK's episodes last year. It was worth the wait! Not only is this cake beautiful, but its delicious. Each layer tastes amazing alone, and outstanding together. It looks like a lot of steps, but it came together pretty quickly!

INGREDIENTS
Bottom Layer
6 tablespoons unsalted butter
7 ounces bittersweet chocolate
3/4 teaspoon instant espresso powder
1 1/2 teaspoons vanilla
4 large eggs, separated
pinch table salt
1/3 cup packed light brown sugar

Middle Layer
2 tablespoons cocoa powder
5 tablespoons hot water
7 ounces bittersweet chocolate
1 1/2 cups cold heavy cream
1 tablespoon granulated sugar
1/8 teaspoon table salt

Top Layer
3/4 teaspoon powdered gelatin
1 tablespoon water
6 ounces white chocolate chips
1 1/2 cups cold heavy cream

Directions for the Bottom Layer. Preheat oven to 325 degrees and butter the bottom and sides of a 9 1/2 inch springform pan. Melt the butter, chocolate, and espresso powder in a double boiler, stirring occasionally until smooth. Remove from heat and cool about 5 minutes. Whisk in vanilla and egg yolks and set aside.

Using an electric mixer, beat the egg whites and salt on medium speed about 30 seconds, add half the brown sugar, beat to combine, add the rest of the sugar and beat at high speed until soft peaks form. Using a whisk, fold 1/3 of the egg whites into the chocolate mixture. Then, using a rubber spatula, fold in remaining egg whites until no white streaks remain. Transfer mixture into springform pan, smoothing top with spatula. Bake until cake has risen and center is just set and still soft (13-18 minutes). Let cool completely, about 1 hour. Do not remove cake from pan.

Directions for the Middle Layer. Once cake is cool, combine cocoa powder and hot water in small bowl and set aside. Melt chocolate in a double boiler, stirring until smooth. Remove and cool 2-5 minutes. Whisk the cocoa powder mixture into the melted chocolate until smooth.

Using an electric mixer, with a whisk attachment, whip the cream, sugar, and salt at medium speed for 30 seconds. Increase speed to high and whip until soft peaks form. Using a whisk, fold 1/3 of the whipped cream into the chocolate mixture, then using a spatula, fold in remaining whipped cream until no white streaks remain. Spoon mousse into springform pan over the cooled cake and gently tap pan on counter to remove any large air bubbles. Gently smooth top with spatula. Refrigerate cake at least 15 minutes while preparing the last layer.

Directions for the Top Layer. In a small bowl, sprinkle gelatin over water and let stand at least 5 minutes. Place white chocolate in a medium bowl. Bring 1/2 cup cream to simmer; take off heat and add gelatin and stir until fully dissolved. Pour hot cream mixture over white chocolate, whisking until chocolate is melted and smooth. Cool to room temperature (will only take 5-10 minutes).

Using an electric mixer with a whisk attachment, whip remaining cup of cream on medium speed for 30 seconds, then increase the speed to high and whip until soft peaks form. Using whisk, fold 1/3 of whipped cream into white chocolate mixture to lighten. Using rubber spatula, fold remaining whipped cream into chocolate mixture until no white streaks remain. Spoon on top of the middle layer, smoothing with a spatula. Return cake to refrigerator and chill until set- at least 2 1/2 hours.

To serve. Use a very sharp (non-serrated) knife that has just been run under hot water to cut each slice. Decorate with shaved or curled chocolate.