1 cup yellow cake mix
1 cup confectioners’ sugar
1/2 stick (1/4 cup) butter, cut into small squares
1/4 cup milk
Mix cake mix and icing sugar in microwave-safe bowl. Add butter and milk. Don’t stir.
Microwave for 2 minutes. Stir immediately until completely combined. Add sprinkles. Do not overmix as sprinkle colour may bleed.
Spread into greased pan. Refrigerate for at least one hour.