Birthday Tie-Dye Cupcakes

Heat oven to 350°F.

Press 1 cookie piece onto bottom of each of 24 paper-lined muffin cups; press 3 of the remaining cookie pieces around inside of each cup.

Prepare cake batter as directed on package; divide into 3 portions. Tint each with different color food coloring; spoon into 3 disposable piping bags. (Do not cut tips off bags.) Place all 3 bags in large resealable plastic bag, positioning tips in one bottom corner of bag.

Use scissors to cut small pieces off tips of piping bags and large piece off corner of resealable bag. Use to pipe batters into muffin cups; swirl gently with knife.

Bake 19 to 22 min. or until toothpick inserted in centers comes out clean. Cool in pans 5 min. Remove to wire racks; cool completely.