Triple Chocolate Mousse Cake

When I saw this cake I knew I had to make it. Chocolate and mousse, plus triple the chocolaty goodness?! Score! :o)

Now in the past, prior to pastry school, I would have seen this recipe and dreamed about how wonderful it would turn out but I would never attempt it. For a few reasons: 1. The long list of ingredients, 2. The even longer list of to-dos, and 3. No spring form pan, and what the heck is folding?! But now that I have experience, a shiny new spring form pan, and big strong folding muscles (who knew folding could be so much work and hurt so bad?), I am ready to take on the world! (The baking world that is.)

So I made the lovely Triple Chocolate Mousse Cake and am very pleased with the way it turned out. My only problem with the recipe is that after the bottom layer is baked, the edges turn in, not allowing for a pretty outer appearance. If I had had the right size cake ring I would have trimmed the cake and built the entire thing in the ring to make for a gorgeous appearance, but I only have little bitty cake rings. Oh well.

Oh yeah, and I really wanted to do chocolate curls on top because how frickin cute are chocolate curls?? But I could not find a large block of chocolate. Guess I have to go to a candy store or order online. Hmmm. Anyhoo! On to the cake!


Triple Chocolate Mousse Cake

Bottom layer:

• 6 tbsp. unsalted butter, cut into 6 pieces (plus extra for greasing the pan)
• 5 oz. bittersweet chocolate, finely chopped
• 2 oz. semi-sweet chocolate, finely chopped
  
• ¾ tsp. instant espresso powder
• 1½ tsp. vanilla extract
• 4 large eggs, separated
• Pinch of salt
• 1/3 cup light brown sugar, packed

Middle layer:

• 2 tbsp. cocoa powder
• 5 tbsp. hot water
• 5 oz. bittersweet chocolate, finely chopped
• 2 oz. semi-sweet chocolate, finely chopped
  
• 1½ cups heavy cream
• 1 tbsp. granulated sugar
• Pinch of salt

Top layer:

• ¾ tsp. powdered gelatin
• 1 tbsp. water
• 6 oz. white chocolate, finely chopped
• 1½ cups heavy cream

Garnish with:

• Chocolate curls or cocoa powder

1. To make the bottom layer, butter the bottom and sides of a 9-inch spring form pan and line with parchment. 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.
   
   
2. 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 spring form pan and smooth the top with a spatula.
   
   
3. 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.
   
   
4. 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.
   
   
5. 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 spring form 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.
   
   
6. To make the top layer, sprinkle the gelatin over the water in a small bowl and let stand 5-8 minutes to allow the gelatin to bloom. 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.
   
   
7. In the clean bowl of a stand mixer fitted with the whisk attachment, whip the remaining 1 cup of cold 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 uncovered and chill until set, at least 2½ hours. (I left mine in overnight and still needed to pop it in the freezer for a bit to get nice clean cuts.) Before cutting, sprinkle with cocoa powder or chocolate curls.

Adapted from Annie's Eats, originally from Cooks Illustrated

-amanda