Mocha Mousse Cake

Heat oven to 350°F (325°F for dark or nonstick pans). Grease and lightly flour bottoms and sides of two 8- or 9-inch round cake pans. In large bowl, beat cake mix, water, oil, 2 tablespoons liqueur and the eggs with electric mixer on low speed 30 seconds, then on medium speed 2 minutes, scraping bowl occasionally. Pour into pans.

Bake 8-inch pans 34 to 40 minutes, 9-inch pans 31 to 37 minutes or until toothpick inserted in center comes out clean. Cool 10 minutes. Run knife around sides of pans to loosen cakes; remove from pans to cooling rack. Cool completely, about 1 hour. Refrigerate layers 45 minutes for easier handling.

Meanwhile, to make mousse, in 2-quart saucepan, mix 1/4 cup of the whipping cream, the granulated sugar and 1/3 cup liqueur. Cook over medium heat, stirring constantly, until sugar is dissolved and mixture simmers; remove from heat. Stir in chocolate chips with whisk until chips are melted. Stir in 2 teaspoons vanilla. Pour into large bowl; cool to room temperature, about 10 minutes.

In chilled medium bowl, beat remaining 1/2 cup whipping cream on high speed just until soft peaks form. Fold whipped cream into chocolate mixture. Cover and refrigerate 30 minutes.

In another chilled medium bowl, beat topping ingredients on high speed until soft peaks form.

Trim off rounded top of one cake layer. Cut each cake layer horizontally to make 2 layers. (To cut, mark side of cake with toothpicks and cut with long, thin knife.) Place 1 layer, cut side up, on serving plate; spread with one-third of the mousse. Repeat with second and third layers. Top with fourth layer, cut side down. Spread topping over side and top of cake. Cover; refrigerate at least 1 hour before serving. Store covered in refrigerator.