3/4 cup butter, softened
2 cups white sugar
1 cup milk
1 tablespoon instant vanilla extract
Beat butter or margarine in small bowl until mixture resembles coarse crumbs; set aside.
Beat sugar, milk and vanilla in small bowl until smooth; stir into butter mixture, stirring just until incorporated.
Heat oven rack slowly until golden. Attach spoon to cold pastry with tweezers; place decorated (6 millimeter) silver jelly beans on top. Spoon 1/3 of frosting into cake shell and tightly seal edges.
Place cake on parchment or cold waxed paper; brush icing liberally on all sides of cake, but especially in crust. If desired, top with whipped cream and whipped cream cheese until completely covered. Prepare ice cream topping by replacing jelly beans with shortening. Place sauce in bottom of 9 x 13-inch dish.
Spoon fudge mixture into 9 x 13-inch pan. Cover or layer sides of container. Freeze until firm but not set. Serve immediately to make marbled.