Chocolate Tuxedo Cake

By Mary-10

Ingredients

• Cake:
• 3 cups all-purpose flour
• 1 tablespoon baking powder
• 1 teaspoon baking soda
• 1/2 teaspoon salt
• 2 cups sugar
• 1 cup unsalted butter, room temperature
• 4 large eggs
• 1 1/3 cup buttermilk
• 2 teaspoons vanilla extract
• 1/4 cup cocoa powder
• 1/2 teaspoon instant espresso powder
• Chocolate Mousse Filling:
• 1 teaspoon unflavored gelatin
• 1/4 cup sugar
• 1/2 cup whole milk
• 1 cup good quality semi-sweet chocolate chips
• 2 teaspoons vanilla extract
• 1 cup cold heavy whipping cream
• White Chocolate Mousse Filling:
• 1 teaspoon unflavored gelatin
• 1/4 cup sugar
• 1/2 cup whole milk
• 1 cup good quality white chocolate chips
• 1/2 teaspoon vanilla extract
• 1 8-ounce container Mascarpone cheese, room temperature
• 1 cup cold heavy whipping cream
• Chocolate Ganache:
• 1/2 cup heavy whipping cream
• 1 cup good quality semi-sweet chocolate chips
• 1/4 teaspoon instant espresso powder
• 2-3 ounces white chocolate chips*

Details

Preparation time 90mins
Cooking time 120mins
Adapted from cakewalker.blogspot.com

Preparation

Step 1

Preheat the oven to 350˚F. Grease the bottom of a 13x18 pan (baker's half sheet). Line with parchment paper. Grease the paper and flour the pan. Set aside.

Sift together the flour, baking powder, baking soda and salt. Set aside.

In a stand mixer fitted with the paddle, cream the butter for a minute. Add the sugar beating for several minutes until the mixture is light and fluffy. Add the vanilla, mixing it in well. Scrape down the bowl. Add one egg at a time beating well after each addition. Scrape the bowl again. Add the mixed flour ingredients alternately with the buttermilk, starting and ending with the flour. Place 2/3rds of the batter into the prepared pan. Return the bowl to the mixer and add the cocoa powder and the coffee powder. Mix until blended and uniform in color. Dot the chocolate batter onto the pan and marble the two colors with a knife. Bake for 30 minutes, or until tooth pick test comes out clean. Cool completely. Flip the pan over to remove cake, gently tapping it out. Remove the paper and cut into thirds, resulting in 3 equal rectangles measuring approximately 5 1/3x13. Can be done one day in advance. Chilling the cake aids the assembly.

Make both flavors of mousse. For the chocolate, stir the gelatin and sugar in a small saucepan. Stir in the milk and let it stand for a couple of minutes to soften the gelatin. Over medium heat, cook the mixture, stirring constantly, until it just begins to boil. Remove from the heat. Quickly add the chocolate chips; stir until melted. Stir in the vanilla. Cool to room temperature. In a chilled bowl using chilled beaters, beat the whipping cream until stiff. Gradually add the chocolate, folding it in gently until no white streaks remain. Cover and refrigerate until set.

For the white chocolate mousse, stir the gelatin and sugar in a small saucepan. Stir in the milk and let it stand for a couple of minutes to soften the gelatin. Over medium heat, cook the mixture, stirring constantly, until it just begins to boil. Remove from the heat. Quickly add the chocolate chips; stir until melted. Stir in the vanilla. Cool to room temperature. Add the mascarpone cheese to the white chocolate mixture; whip until blended and smooth. In a chilled bowl using chilled beaters, beat the whipping cream until stiff. Gradually add the chocolate/cheese mixture, folding it in gently until uniform in color. Cover and refrigerate until set. Both mousse flavors can be made 1 to 3 days in advance.

To assemble, place one cake rectangle onto a platter. Stir the dark chocolate mousse with a spoon, and spread evenly on top of the cake. Place more emphasis on spreading the mousse to a uniform thickness as close as possible to the edges versus spreading it perfectly to each edge. Fit another cake on top of the mousse. Give the white chocolate mousse a stir, then spread evenly on top of the second layer in the same manner as the previous step. Place the final cake on the top. Set aside.

Meanwhile, make the ganache. In a heat proof measuring cup, heat the cream in the microwave (or bring to a light simmer in a saucepan on the stove) on short 20-30 second intervals until it just begins to bubble and steam. Place the chocolate chips and espresso granules in a small mixing bowl; pour the hot cream over the chocolate. Let the heat of the cream soften the chocolate for a minute, then gently stir with a whisk until well blended, smooth and shiny.

Pour a good amount of the warm ganache onto the top of the cake. Use an offset spatula to spread the chocolate evenly to the edges. Use more if needed, but the recipe yields an ample amount of ganache with a bit leftover.

*Decorative White Chocolate option: Gently melt the 2-3 ounces white chocolate chips in a double-boiler, immediately transfer the chocolate to a resealable plastic bag, squeezing the chocolate towards a corner of the bag. Snip the tip of the corner with scissors to make a small opening. With the cake horizontally in front of you, snake a line of white chocolate vertically across the surface of the ganache from one end to the other. Leave about a half inch space between each "S" curvature. While both the ganache and the white chocolate are still warm, draw a knife tip horizontally in one direction through the white chocolate. Skip a space (about a half inch) and draw another line horizontally in the opposite direction. Repeat a few more times, spacing evenly, to create the pattern depicted in the photo.

Gently wrap the sides of the cake with plastic film. Place the cake in the refrigerator to set the chocolate ganache topping, about one hour. Take the cake from the refrigerator and remove the wrap. Using a long sharp knife, trim off all four sides of the cake to even the edges. Dipping the knife in hot water between cuts, then shaking off the excess water makes trimming easier. For "cleaner" trimming, cut the cake in a frozen state. The trimmings make up more than a portion of cake—perfect to share with your "little chefs" running around in the kitchen!