Break 1/2 or a little more of an angel food cake in small pieces. Cover the bottom of a 9"x13" pan with cake pieces.
Whip butter, egg yolks, powdered sugar and vanilla until light and fluffy. Whip the whipping cream and add to above mixture. Pour cream mixture over cake pieces. Then sliver Butterfinger candy bars and sprinkle over cream mixture. Refrigerate overnight.