The Best of America's Test Kitchen 2010 Cookbook and this recipe's photo graced the cover. A few days later, I happened to catch the episode of From America's Test Kitchen on PBS where they made this cake. Two days ago, was my husband, Jay's birthday. As if it were ordained, I had to make this cake. With the bottom layer a flourless chocolate cake, the middle a silky chocolate mousse and the top a light and creamy white chocolate mousse, how could you go wrong?
After showing him the picture from the cookbook, Jay thought it looked like the makings a pretty good birthday cake. I was very happy to oblige, and even happier when I realized that I had everything to make the bottom layer, on hand and could crank that out the night before.
Despite the lengthy instructions, it was really quite simple and only required a bit of time. It's definitely worth making for a special occasion. Clearly, I need more practice in making sure the layers come out more even and working on my chocolate shavings (how wimpy did those turn out???), but it was met with rave reviews. I don't think I'll mind having to work out the kinks in this one, especially when that includes getting to lick the bowl... : )
Happy Birthday, Honey!
6 tablespoons (3/4 stick) unsalted butter, cut into pieces
7 ounces bittersweet chocolate
3/4 teaspoon instant espresso powder (Starbucks via works very well)
1 1/2 teaspoon vanilla extract
4 large eggs, separated
1/3 cup packed light brown sugar
For the middle layer:
2 tbsp. cocoa powder, preferably Dutch-processed
5 tbsp. hot water
7 oz. bittersweet chocolate, finely chopped
1½ cups heavy cream
1 tbsp. granulated sugar
Pinch of salt
For the top layer:
¾ tsp. powdered gelatin
1 tbsp. water
6 oz. white chocolate, finely chopped
1½ cups heavy cream
Chocolate curls or cocoa powder
To make the bottom layer, butter the bottom and sides of a 9-inch springform pan. Center a rack in the oven and preheat to 325˚ F. Combine the butter, chocolate, and espresso powder in a large heatproof bowl set over simmering water. Stir occasionally until the mixture is smooth. Remove from the heat and let cool slightly, about 5 minutes. Whisk in the vanilla and egg yolks. Set aside.
In a stand mixer fitted with the whisk attachment, beat the egg whites and salt on medium speed until foamy, about 30 seconds. Crumble half of the brown sugar into the mixing bowl with your fingers to remove any lumps. Beat until incorporated, about 15 seconds. Add the remaining brown sugar and continue to beat on high speed until stiff peaks form, about 1 minute more. Using a whisk, mix one-third of the beaten egg whites to the chocolate mixture to lighten it. Fold in the remaining egg whites gently with a rubber spatula until no streaks remain. Pour the batter into the prepared springform pan and smooth the top with a spatula.
Bake until the cake has risen, is firm around the edges and the center has just set but is still soft (should spring back after pressing gently with a finger), about 14-18 minutes. Transfer the cake to a wire rack to cool completely, at least 1 hour. Do not remove the cake from the pan. (If not making the second layer right away, cover with plastic wrap and refrigerate until ready to proceed.)
To make the second layer, whisk together the cocoa powder and hot water in a small bowl; set aside. Melt the chocolate in a heatproof bowl set over simmering water, stirring occasionally until smooth. Once melted, remove from the heat and let cool slightly, 2-5 minutes.
In the clean bowl of a stand mixer fitted with the whisk attachment, whip the cream, sugar and salt on medium speed until the mixture begins to thicken, about 30 seconds. Increase the speed to high and whip until soft peaks form when the whisk is lifted, 30-60 seconds. Whisk in the cocoa powder
mixture until smooth. Using a whisk, mix one-third of the whipped cream to the chocolate mixture to lighten it. Fold in the remaining whipped cream gently with a rubber spatula until no streaks remain. Pour the mousse into the springform pan over the cooled cake and tap gently on the counter 3 times to remove air bubbles. Gently smooth the top with a spatula. Wipe the inside edge of the pan to remove any drips. Refrigerate for at least 15 minutes while preparing the top layer.
To make the top layer, sprinkle the gelatin over the water in a small bowl and let stand at least 5 minutes to soften. Place the white chocolate in a medium bowl. Bring ½ cup of the cream to a boil in a small saucepan. Remove the pan from the heat, add the gelatin mixture and stir until dissolved. Pour the hot cream mixture over the white chocolate and let stand about 1 minute. Whisk until the mixture is smooth. Cool to room temperature, about 5-8 minutes, stirring occasionally.
In the clean bowl of a stand mixer fitted with the whisk attachment, whip the remaining 1 cup of cream at medium speed until it begins to thicken. Increase the speed to high and whip until soft peaks form when the whisk is lifted, 30-60 seconds. Using a whisk, mix one-third of the whipped cream to the white chocolate mixture to lighten it. Fold in the remaining whipped cream gently with a rubber spatula until no streaks remain. Spoon the white chocolate mousse into the pan over the middle layer. Smooth the top with an offset spatula. Return the cake to the refrigerator and chill until set, at least 2½ hours (Also, make sure not to cover your finished cake with plastic wrap as it will stick to the top and mess up the pretty smooth surface).
Remove from fridge preferably 20 minutes before serving (I didn't do this and it was ok, just a little messy to cut). To serve, run a knife around the edge of the spring form pan and gently remove sides of pan. Top with chocolate curls or cocoa powder to garnish. To slice as cleanly as possible, dip a knife into hot water and wipe off immediately before making each slice.
Cake can be made and stored a day ahead.
Recipe Source: The Best of America's Test Kitchen 2010 Cookbook
I'm linking this recipe to Cast Party Wednesday--Check it out for some great recipes ideas!