HEAT oven to 350°F.
PREPARE cake batter and bake as directed on package for 24 cupcakes. Cool cupcakes in pans 10 min. Remove to wire racks; cool completely.
EMPTY nonpareils into small bowl. Spoon frosting into medium bowl. Add COOL WHIP; whisk until blended. Spread onto cupcakes. Dip tops, 1 at a time, into nonpareils.
USE decorating gel to decorate cupcakes to resemble baseballs as shown in photo.