Double Chocolate Bar Cake

Cake:
7 ounces milk chocolate, broken into bits
1/2 cup butter or margarine, softened
1 cup boiling water
2 cups all-purpose flour
5 1/2 cups granulated sugar
1/2 cup unsweetened cocoa powder
2 teaspoons baking soda
1 teaspoon salt
2 eggs
1/2 cup sour cream
1 teaspoon vanilla

Frosting:
1 cup powdered sugar
1/2 cup unsweetened cocoa powder
2 cups whipping cream
2 teaspoons vanilla


Preheat oven to 350 degrees. Grease and flour three 9-inch round baking pans. In a small bowl, stir together chocolate bar pieces, butter and water until chocolate melted. In a large mixer bowl, stir together flour, sugar, cocoa powder, baking soda and salt. Gradually add chocolate mixture, beating on medium speed until well blended. Add eggs, sour cream and vanilla; beat until well blended. Beat on medium speed 1 minute. Pour batter into prepared pans. Bake 25-30 minutes or until wooden pick inserted in center comes out clean. Let cool 10 minutes; remove from pans to wire racks. Let cool completely. To prepare frosting: In large mixer bowl, stir together sugar and cocoa powder. Add cream and vanilla; beat until stiff. Use to fill and frost cake. Refrigerate any leftover cake.