Big-Top Carnival Cake

Prepare the cake pans: Preheat oven to 350°F. Lightly coat two 8-inch cake pans with softened butter. Cut two 8-inch circles out of parchment paper and fit them into the bottom of the cake pans. Lightly coat the paper circles with butter and set aside.

Make the batter: Combine 1 cup of boiling water with the cocoa in a medium bowl. Stir in the buttermilk and set aside. Sift together flour, baking soda, and salt in a medium bowl and set aside. Beat the butter in a large bowl until light and fluffy with a mixer set on medium speed. Add sugar and mix until combined. Add the vanilla and the eggs, one at a time, beating after each addition, until the mixture is smooth and light. In thirds, alternately add the flour mixture and the buttermilk mixture, blending well after each addition until smooth.

Bake the cake: Pour batter into the prepared pans and bake until a tester inserted into the center of each cake comes out clean -- about 45 minutes. Cool the cakes, in the pans, on a wire rack for 30 minutes. Release the cakes from pans and cool completely on the rack.

Frost the cake: Transfer 1 cup White-Chocolate Cream-Cheese Frosting to a small bowl, stir in the color of your choice, and set aside. Place one cake layer on a serving plate and top with 1 cup of the remaining frosting. Spread frosting evenly over the first layer and top with the second cake layer. Cover the entire cake with a thin coating of frosting and chill for at least 1 hour. Remove cake from refrigerator and frost with remaining icing. Fill a pastry bag fitted with a decorating tip (such as a star or shell) with the colored icing and decorate the cake as desired. Store covered and refrigerated for up to 2 days. Let stand at room temperature for 15 minutes before serving.