Preheat oven to 350°F. Grease and flour 10 inch tube pan.

Prepare, bake and cool cake following package directions. Split cake horizontally into three layers; set aside. Chop 11 candy bars into pea size pieces. Whip cream until stuff peaks form. Fold candy pieces into whipped cream.

To assemble, place one split cake layer on serving plate. Spread 1 1/2 cups whipped cream mixture on top. Repeat with remaining layers and whipped cream mixture. Frost sides and top with remaining filling. Chop remaining candy bar coarsely. Sprinkle over top. Refrigerate until ready to serve.