Heat oven to 375°F. Place 24 of the paper baking cups in each of 24 regular-size muffin cups. Make cake mix as directed on box, using water, oil and eggs. Using about 1/2 of the batter, spoon about 1 rounded tablespoon batter into each muffin cup. Chill remaining batter. Bake 12 to 16 minutes or until toothpick comes out clean. Remove from pans to cooling rack. Repeat with remaining baking cups and batter. Cool completely.