Break up angel food cake in bottom of a 9x13 cake pan.
Beat Egg yolks, powdered sugar, and butter until a nice light yellow. Fold in Cool Whip. Crush the butterfingers (its easier to do if you keep the in the freezer for a bit before you do this step) Pour half of butterfingers into cool whip mixture.
Then spoon or pour over the angel food cake. Sprinkle remaining butterfingers over the top. Keep in Fridge.