Ingredients
3/4 cup butter, softened1-1/2 cups sugar1 large egg1 teaspoon vanilla extract1 cup buttermilk3/4 cup sour cream2 cups all-purpose flour2/3 cup baking cocoa1 teaspoon baking soda1/4 teaspoon saltFILLING:8 ounces semisweet chocolate, chopped2 cups heavy whipping cream1 teaspoon vanilla extractGANACHE:16 ounces semisweet chocolate, chopped1/2 cup butter, cubed1-1/2 cups heavy whipping cream
Preparation
Preheat oven to 350°. Line the bottoms of 2 greased 8-in. round cake pans with parchment; grease paper. In a large bowl, cream butter and sugar until light and fluffy, 5-7 minutes. Beat in egg and vanilla. Combine buttermilk and sour cream. Combine flour, cocoa, baking soda and salt; add to creamed mixture alternately with buttermilk mixture, beating well after each addition.
Pour into prepared pans. Bake until a toothpick inserted in center comes out clean, 30-35 minutes. Cool for 10 minutes; remove from pans to wire racks to cool completely.
In a heavy saucepan, melt chocolate with cream over low heat. Remove from the heat; stir in vanilla. Transfer to a large mixing bowl; chill until slightly thickened, stirring occasionally. Beat on medium speed until light and fluffy. Chill until mixture achieves spreading consistency.
For ganache, in a heavy saucepan, melt chocolate and butter. Gradually add cream; heat until just warmed. Chill until slightly thickened mixture achieves spreading consistency.
Using a long serrated knife, cut each cake horizontally in half. Place 1 cake layer on a serving plate. Pipe a circle of filling around top edge of layer; spread one-third of the filling inside frosting. Repeat twice. Top with remaining cake layer. Spread ganache over top and sides of cake.
