HEAT oven to 350°F.
PREPARE cake batter and bake as directed on package for 2 (9-inch) round cake layers, blending dry pudding mix into batter before pouring into prepared pans. Cool cakes in pans 15 min. Invert onto wire racks; gently remove pans. Cool cakes completely.
MIX cherry pie filling and kirsch. Reserve 1/2 cup each of the cherry mixture and COOL WHIP for garnish; spoon remaining cherry mixture onto 1 cake layer on plate. Cover with 1 cup of the remaining COOL WHIP and second cake layer.
SPREAD 1-1/2 cups of the remaining COOL WHIP onto top and side of cake. Top with dollops of the remaining COOL WHIP. Garnish with reserved cherry mixture and grated chocolate. Keep refrigerated.