Makes one 2-layer cake

One layer is an ordinary cake, but when it sits on top of another layer it becomes much more than the sum of its parts. Two layers is a party cake that calls for balloons, flowers, and candles. Here, a double-decker yellow cake lavishly frosted with chocolate buttercream is the perfect dessert for happy celebrations.

CAKE

Butter (for the pans)

4 ounces white chocolate, coarsely chopped

2⅓ cups flour

2¼ teaspoons baking powder

¼ teaspoon salt

¾ cup (1½ sticks) unsalted butter, at room temperature

1¼ cups granulated sugar

4 eggs

1½ teaspoons vanilla extract

1 cup milk

1. Set the oven at 350 degrees. Butter two 9-inch round cake pans. Line the pans with parchment paper cut to fit; butter the paper.

2. In a heatproof bowl set over a saucepan of barely simmering water, melt the white chocolate, stirring often. Remove the bowl from the water and wipe the bottom dry.

3. In another bowl, whisk the flour, baking powder, and salt to blend them.

4. In an electric mixer on medium speed, beat the butter and granulated sugar until well blended. Beat in the eggs, one at a time, followed by the vanilla and white chocolate.

5. With the mixer set on its lowest speed, blend in the flour mixture alternately with the milk until blended. Divide the mixture between the pans and smooth the tops. Bake the cakes for 35 minutes or until a skewer inserted in the centers comes out clean.

6. Set the pans on wire racks to cool for 10 minutes. Remove the cakes from the pans, peel off and discard the parchment papers, and turn the cakes right side up. Cool completely.

FROSTING

4 ounces unsweetened chocolate, coarsely chopped

½ cup (1 stick) unsalted butter, at room temperature

2¾ cups confectioners’ sugar

½ cup heavy cream, or more if needed

1 teaspoon vanilla extract

1. In a heatproof bowl set over a saucepan of barely simmering water, melt the unsweetened chocolate, stirring often. Remove the bowl from the water and wipe the bottom dry.

2. In an electric mixer set on medium speed, beat the butter until creamy. With the mixer set on its lowest speed, gradually beat in 2 cups of the confectioners’ sugar followed by the unsweetened chocolate, ¼ cup cream, vanilla, and the remaining ¾ cup sugar. Add the remaining ¼ cup cream, 1 tablespoon at a time, and beat until smooth and creamy. If necessary, add more cream, 1 tablespoon at a time.

3. Set 1 cake layer, bottom side up, on a serving plate. Use an offset spatula to spread about 1 cup of the frosting on top. Set the remaining cake layer, right side up, on top. Spread remaining frosting on top and sides of cake. Jean Kressy

Jean Kressy can be reached at jeankressy@comcast.net