Chocolate mousse is one of my all time favorite desserts. It’s relatively quick and easy, and is always impressive. So, when I saw a recipe that takes that love, and multiplies it times three, and then puts it into the form of a cake – lets just say it took my breath away. I made this cake for Valentine’s Day, and I was kind of worried that I’d be pressed for time. It’s quite a lengthy recipe, but don’t let that intimidate you. As with most Cook’s Illustrated recipes, it looks a lot worse than it is. But, it’s their descriptiveness and attention to detail that always make their recipes sure fire winners. I worked on it here and there all morning, and by lunchtime the cake was done and chilling in the refrigerator.
It was all I could do to wait until after dinner to unmold and serve it. I’m pleased to report that it’s everything I thought it was going to be. Often chocolate desserts are so sweet they hurt your teeth. Not the case here. The use of bittersweet chocolate really creates a great balance. I’m not a big fan of white chocolate, but the extra boost of sweetness it lends to the top layer is welcome. This will definitely be a new addition to my repertoire of special occasion desserts. It was just perfect!
Triple Chocolate Mousse Cake
For the bottom layer:
6 tablespoons unsalted butter, cut into six pieces
7 ounces bittersweet chocolate, chopped fine
3/4 teaspoon instant espresso powder
4 large eggs, separated
1 1/2 teaspoons vanilla extract
Pinch salt
1/3 cup packed light brown sugar
For the middle layer:
5 tablespoons hot water
2 tablespoons cocoa powder
7 ounces bittersweet chocolate, chopped fine
1 1/2 cups heavy cream, chilled
1 tablespoon granulated sugar
1/8 teaspoon salt
For the top layer:
3/4 teaspoon powdered gelatin
1 tablespoon water
6 ounces white chocolate chips
1 1/2 cups heavy cream, chilled
Shaved chocolate or cocoa powder for decorating, optional
To prepare the bottom layer, preheat oven to 325º. Grease a 9- or 9 1/2-inch springform pan. Combine butter, chocolate and espresso in a large heatproof bowl set over a pan of barely simmering water. Stir occasionally until melted and smooth. Remove from heat and allow to cool slightly, about 5 minutes. Whisk in egg yolks and vanilla and set aside.
Using a stand mixer fitted with the whisk attachment, whip egg whites and salt on medium-low speed until foamy, about 1 minute. Add half of sugar and continue whipping until combined, about 15 seconds. Add remaining sugar, increase speed to high, and whip until soft peaks form, 1 additional minute, scraping down bowl halfway through. Using a whisk, fold one-third of the egg whites into the chocolate mixture to lighten it. Fold in remaining egg whites using a rubber spatula. When no white streaks remain, carefully transfer batter to prepared pan. Smooth top with spatula. Bake cake until it has risen, is firm around the edges and just set in the center (cake center should spring back when gently pressed with finger), 13 to 18 minutes. Transfer to a wire rack to cool completely, about 1 hour. Do not remove cake from pan.
While cake is cooling, prepare middle layer. Combine the hot water and cocoa in a small bowl and set aside. Place chocolate in a large heatproof bowl set over a pan of barely simmering water. Stir occasionally until melted and smooth. Remove from heat and allow to cool slightly, 2 to 5 minutes.
Using a stand mixer fitted with the whisk attachment, whip cream, sugar and salt on medium-low speed until foamy, about 1 minute. Increase speed to high and whip until soft peaks form, 1-3 minutes. (It helps to chill the mixing bowl before whipping the cream.) Whisk cocoa mixture into chocolate. Using a whisk, fold one-third of the cream into the chocolate mixture to lighten it. Fold in remaining cream using a rubber spatula. When no white streaks remain, spoon mousse onto cooled cake. Smooth top with spatula and gently tap on counter to release any air bubbles. Wipe inside edge of pan with a damp cloth or paper towel to remove any drips. Refrigerate for at least 15 minutes while preparing top layer.
To prepare the top layer, sprinkle gelatin over water and let sit for at least 5 minutes. Place white chocolate in a medium heatproof bowl. Bring 1/2 cup of cream to a simmer in a small saucepan over medium-high heat. Remove from heat and stir in gelatin mixture until completely dissolved. Pour cream mixture over white chocolate, cover and allow to sit for 5 minutes. Whisk gently until smooth. Let cool to room temperature, stirring occasionally (mixture will thicken slightly during this time).
Using a stand mixer fitted with the whisk attachment, whip remaining cup of cream on medium-low speed until foamy, about 1 minute. Increase speed to high and whip until soft peaks form, 1 to 3 minutes. Using a whisk, fold one-third of cream into white chocolate to lighten it. Fold in remaining cream using a rubber spatula. When no white streaks remain, spoon white chocolate mousse into the pan over the middle layer. Smooth top with a rubber spatula. Return to refrigerator and chill until set, at least 2 1/2 hours. Cake can be refrigerated up to 1 day. Allow to sit at room temperature for about 45 minutes before slicing.
To serve, garnish cake with chocolate curls or dust with cocoa if desired. Run a thin knife between the cake and sides of pan. Remove sides and run the cleaned knife along the outside to smooth. Cut using cheese wire or a hot knife, cleaning and drying between each cut.
Source: The Cook’s Illustrated Cookbook; via Cook Like A Champion
