1 pkg. (2-layer size) chocolate cake mix
1 cup water
1/2 cup BREAKSTONE'S or KNUDSEN Sour Cream
1/3 cup oil
2 cups thawed COOL WHIP Whipped Topping
1 oz. BAKER'S Semi-Sweet Chocolate
1/2 oz. BAKER'S White Chocolate
20 JET-PUFFED Marshmallows
3 Tbsp. assorted colored sugars
1. HEAT oven to 350ºF.
2. BEAT first 5 ingredients with mixer 2 min. or until blended; pour into 13x9-inch pan sprayed with cooking spray. Bake 35 min. or until toothpick inserted in center comes out clean. Cool completely. Invert cake onto cake board or tray. Frost with COOL WHIP.
3. MELT chocolates as directed on packages. Draw 7x5-inch skull shape on piece of paper; tape onto piece of cardboard. Wrap tightly with plastic wrap. Trace around pattern with melted semi-sweet chocolate, then fill in pattern with remaining melted semi-sweet chocolate. (See Tip.) Refrigerate 10 min. or until firm. Remove plastic wrap and chocolate shape from cardboard; invert chocolate skull onto center of cake. Discard plastic wrap. Draw skull's face with melted white chocolate piped from separate bag.
4. USE clean kitchen shears to cut each large marshmallow crosswise into 5 pieces; dip cut sides in colored sugars. Decorate cake with marshmallow flowers, pressing 5 marshmallow pieces, cut-sides up, together to make each flower. Sprinkle remaining colored sugars onto centers of flowers. Keep refrigerated.
How to Pipe Melted Chocolate - Spoon melted chocolate into small resealable plastic bag. Press out excess air and seal bag. Cut small piece (about 1/8 inch) from one bottom corner of bag. Use to trace and fill in skull pattern with chocolates as directed.
How to Easily Cut Marshmallows - Use clean kitchen shears to cut marshmallows into pieces as directed, dipping shears in warm water and wiping dry with paper towel between cuts to prevent sticking.