ADD 1 Tbsp. dry gelatin mix and food colorings to frosting in medium bowl; stir gently with whisk until blended. Stir in COOL WHIP. Refrigerate until ready to use.
PREPARE cake batter and bake as directed on package for 24 cupcakes, blending remaining dry gelatin mix into batter before spooning into prepared cups. Cool completely.
SPREAD cupcakes with COOL WHIP mixture. Decorate with remaining ingredients.