PREPARE cake batter according to package directions. Pour into 3 greased and floured 8 inch round cakepans.Bake at 325 for 25 minutes. Cool in pans for 10 minutes on wire racks. Remove from pans and cool completely on wire racks.
BEAT cream cheese, powdered sugar and granulated sugar at medium speed until mixture is creamy... CHOP candy bars finely. Fold cream cheese mixture and 1/2 of the chopped candy into Cool Whip...SPREAD icing between layers and on top of cake. Sprinkle half of the chopped candy bars over top and sdes of cake.