Semisweet Chocolate Layer Cake with Vanilla Cream Filling
10 servings
Cake
1/2 cup natural unsweetened cocoa powder
2 ounces semisweet or bittersweet chocolate (do not exceed 61% cacao), chopped
1/2 cup boiling water
1/2 cup buttermilk
1-1/3 cups cake flour
1 teaspoon baking soda
1/2 teaspoon salt
1-1/3 cups (packed) golden brown sugar
1/2 cup (1 stick) unsalted butter, room temperature
2 large eggs
1 teaspoon vanilla extract
Cream Filling
3 tablespoons cold water
1-3/4 teaspoons unflavored gelatin
2-1/4 cups chilled heavy whipping cream, divided
1/2 cup powdered sugar
1 teaspoon vanilla extract
Ganache
1-1/4 cups heavy whipping cream
1/3 cup light corn syrup
16 ounces semisweet or bittersweet chocolate (do not exceed 61% cacao), chopped
1 teaspoon vanilla extract
Unsweetened cocoa powder or powdered sugar
CAKE: Position rack in center of oven and preheat oven to 350 degrees F. Butter three 8-inch-diameter cake pans with 2-inch-high sides. Line pan bottoms with parchment paper; butter parchment. Combine cocoa powder and semisweet chocolate in medium bowl. Pour 1/2 cup coiling water over cocoa powder and chocolate and whisk until smooth. Whisk in buttermilk. Set chocolate mixture aside.
Whisk flour, baking soda, and salt in another medium bowl to blend. Using electric mixer, beat brown sugar and butter in large bowl until well blended (mixture will not be smooth). Add eggs and vanilla and beat until light and creamy. Beat in dry ingredients and chocolate mixture. Transfer batter to prepared pans, dividing equally. Bake cakes until tester inserted into center comes out clean, about 15 minutes. Cool cakes in pans on racks 15 minutes. Cut around pan sides to loosen cakes. Turn cakes out onto racks; peel off parchment. Cool completely.
CREAM FILLING: Place 3 tablespoons cold water in small bowl. Sprinkle gelatin over. Let stand until gelatin softens, about 10 minutes. Bring 1/2 cup cream just to simmer in heavy small saucepan. Add hot cream to softened gelatin; stir until gelatin dissolves. Place in refrigerator just until cool but not set, stirring frequently, 5 to 8 minutes. Using electric mixer, beat remaining 1-3/4 cups cream, sugar, and vanilla in medium bowl until peaks form. Gradually add gelatin mixture, beating until medium-firm peaks form.
Place 1 cake layer on 8-inch cardboard round or tart pan bottom. Spread half of filling over. Top with second cake layer. Spread remaining filling over. Top with third cake layer. Using icing spatula, remove any excess filling that may have oozed out between layers. Chill on cardboard round until filling sets, about 2 hours.
GANACHE: Meanwhile, bring cream and corn syrup to simmer in heavy small saucepan. remove from heat. Add chocolate; whisk until smooth. Stir in vanilla. Cool until thick enough to spread, about 2 hours.
Place cake, still on cardboard, on rack set in center of baking sheet. Spread 1/4 of ganache over top and sides of cake. Chill cake 15 minutes. Spread 1/4 of remaining ganache over top and sides of cake again. Chill cake 1 hour. Rewarm remaining ganache in small saucepan over low heat just until lukewarm and pourable, stirring constantly. Pour ganache over cold cake, spreading as needed to cover top and sides. Chill until ganache is set, about 2 hours.
DO AHEAD: Can be made 1 day ahead. Keep chilled. Let stand at room temperature 2 hours before continuing.
Cut out paper heart shapes of differing sizes and lay flat atop cake. Sift cocoa powder or powdered sugar over. Carefully lift hearts from cake, revealing design, and serve.
