Mocha Layer Cake #SundaySupper
An exquisite layered mocha cake adapted from Tom Douglas
- Prep Time: 60 mins
- Cook Time: 25 mins
- Total Time: 1 hour 25 minutes
- Yield: 12 servings 1x
- 2 cups flour
- 1/4 cup unsweetened cocoa powder
- 1 cup plus 1 tablespoon granulated sugar, divided
- 1/2 teaspoon baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon salt
- 2 eggs, at room temperature
- 1/3 cup dark brown sugar
- 1 cup vegetable oil
- 2 1/2 ounces bittersweet chocolate, melted
- 1 cup buttermilk
- 1–3 teaspoons instant coffee
- 2 teaspoons vanilla extract
Milk Chocolate Mousse::
- 1/2 teaspoon unflavored gelatin (I use Knox brand)
- 1/2 tablespoon water
- 1/2 cup cold heavy cream
- 2 tablespoons Kahlua or other coffee liqueur
- 2 egg yolks
- 2 tablespoons sugar
- Pinch of salt
- 4 ounces milk chocolate, melted and cooled
Chocolate Swiss Meringue Buttercream::
- 1 cup sugar, processed in food processor until powdery
- 3 large egg whites
- 1/4 teaspoon salt
- 1/2 teaspoon pure vanilla extract
- 2 sticks plus 2 tablespoons butter (9 ounces), cut into tablespoons, at room temperature
- 4 ounces bittersweet or semisweet chocolate, melted and cooled
- Preheat the oven to 350°. Spray two 9-inch round cake pans with Baker’s Joy or any flour/oil spray. Line the bottoms with parchment paper and spray those as well.
- Whisk together the flour and cocoa powder with ½ cup of the granulated sugar, and the baking powder, baking soda and salt.
- In your stand mixer fitted with the whisk, beat the eggs with the brown sugar and the remaining ½ cup plus 1 tablespoon of granulated sugar at medium-high speed until thick, about 5 minutes. At medium speed, gradually add ½ cup of the oil and beat for 3 minutes. Beat in the melted chocolate, then slowly add the rest of the oil, until thoroughly blended, scraping the side and bottom of the bowl. Whisk the instant coffee (use 1 teaspoon for a subtle coffee boost and 1 tablespoon for a more obvious mocha flavor) into the buttermilk. At low speed, beat in the buttermilk and vanilla. Remove the bowl from the mixer and gently mix in the dry ingredients by hand.
- Pour the cake batter into the prepared pans and bake for about 25 minutes, until a toothpick inserted in the cakes comes out with only a few moist crumbs. Cool the cakes in the pans for 20 minutes, then remove from pans to a rack to finish cooling. Peel off the parchment paper.
- To make the mousse, pour the water into a small bowl and sprinkle the gelatin over the surface. Let stand until softened.
- Next, in a medium bowl, beat the cream until soft peaks are formed. Refrigerate to chill, about 10 minutes.
- In a small, microwave-safe bowl, heat the coffee liqueur until hot, about 30 seconds.
- In another bowl, beat the egg yolks with the sugar and salt at high speed until pale and thick, about 5 minutes. While beating the yolks, mix in coffee-gelatin liquid; scrape the side and bottom of the bowl. Beat in the melted chocolate. Using a rubber spatula, fold in the whipped cream in 2 additions. Transfer the mousse to a bowl, cover with plastic wrap and chill for 4 hours or more.
- When mousse is almost done chilling, make the frosting.
- Put the sugar in a medium heatproof bowl ( I used my metal stand mixer bowl) and whisk in the egg whites and salt. Set the bowl over a saucepan of simmering water and whisk gently until the sugar is completely dissolved, 5 minutes.
- Transfer the egg-white mixture to the bowl of a standing electric mixer fitted with the whisk. Add the vanilla and beat at medium-high speed until stiff and glossy, about 8 minutes. Beat in the butter a few pieces at a time, making sure it is fully incorporated before adding more. If the mixture ever appears runny, place in the refrigerator to thicken up, then continue.
- Beat in the melted chocolate until fully incorporated, scraping down the bowl as needed.
- Set one cake layer on a platter. Spread the mousse filling on top and cover with the second layer. Frost the cake with the buttercream. Refrigerate the cake until the frosting is firm.