Butter 3 (8-inch) cake pans and line with parchment paper.
For Chocolate Layer: Microwave 2 tablespoons butter and chocolate on HIGH in a large glass bowl for 30 second intervals until melted; toss with ½ (16-ounce) package marshmallows. Microwave on HIGH 1 to 1 ½ minutes or until puffed and melted. Immediately stir in 4 cups puffed rice cereal, mixing well. Press into one prepared pan with wet fingers. Let stand 30 minutes or until firm.
For Vanilla Layer: repeat procedure omitting chocolate.
For Strawberry Layer: repeat procedure omitting chocolate and using strawberry marshmallows.
Spread ½ cup frosting between layers. Cut into 8 wedges. Decorate each wedge with a dollop of frosting and a cherry.