1Heat oven to 350°F (325°F for dark or nonstick pans). Grease or spray bottoms and sides of two 8- or 9-inch round pans. Make, bake and cool cake as directed on box for 8- or 9-inch rounds. Wrap and freeze 1 layer for later use. Freeze remaining layer 45 minutes before cutting to reduce crumbs.
2Cut off rounded top of cake to make flat surface; place cake cut side down. Cut cake in half crosswise; cut each half into 1/3 and 2/3 pieces (as shown in diagram). Place cake pieces on platter to form butterfly. Gently separate cake pieces to form wings.
3Reserve 1/2 cup frosting; set aside. Spread top and sides of cake with thin layer of frosting to seal in crumbs. Refrigerate or freeze 30 to 60 minutes to set frosting. Frost cake with remaining frosting. Place candy stick between cake pieces for butterfly body.
4Stir food color into reserved frosting until well blended. Spread over cake in desired pattern on wings. Outline wing patterns with gel. Sprinkle with sugar crystals. Place jelly beans on corners of wings. Decorate butterfly with candy decorations. Store loosely covered.