PREHEAT oven to 350° F. Grease or paper-line 24 muffin cups.
PREPARE cake mix batter according to package directions; stir in 1/2 cup Butterfinger. Spoon into prepared muffin cups.
BAKE for 15 to 25 minutes or until wooden pick inserted in cupcake comes out clean. Cool completely. Frost; sprinkle with remaining Butterfinger.