Make and bake cake mix according to directions.
Bake in two 9" round pans, sprayed with Pam and bottoms covered with waxed paper rounds.
Bake 350* 25 minutes
Filling: Beat filling ingredients with electric mixer on high speed until light and fluffy.
On serving plate, place 1 cooled cake layer, rounded side down.
Spread filling over cake, spreading slightly over edge.
Top with second cooled cake layer, rounded side up.
Ganache: Heat whipping cream about 30 seconds in microwave, until hot but not boiling. Stir in chocolate until melted. Cool about 10 minutes.
Pour ganache onto top of cake; spread until it just begins to flow over edge of cake.
Store loosely covered