INSTRUCTIONS :
Bake the cake according to package directions using a 9×13-in. baking pan.
Mix the pudding mix with 2 cups of milk in a medium bowl.
Poke holes in the hot cake with the round end of a wooden spoon and slowly pour this mixture over the cake, trying to fill the holes.
Microwave the chocolate topping (with the lid off) for about 45 seconds or until it pours easily. Pour evenly over the top of the cake.
Let the cake cool completely.
In a medium bowl, combine the second pudding mix with the additional 2 cups of milk. Carefully fold in the whipped topping. Spread the mixture evenly over the top of the cake. Sprinkle the chopped candy bar over the top.
Refrigerate for at least 4 hours. Store the cake (covered) in the refrigerator.
