PREPARE cake batter and bake in 13x9-inch pan as directed on package. Cool cake in pan 15 min. Pierce cake at 3/4-inch intervals with handle of wooden spoon, using turning motion to make large holes.

Put them back in the refrigerator after you've toasted the marshmallow creme ... but should be wrapped loosely in foil or plastic so the cake part doesn't dry out. To keep the wrapping material ...