This is a recipe where you will want to leave a spoon in it because everytime you go into the refrigerate you will want to take a taste. When I make it I use sugar free pudding, fat free cool whip, skim milk, low fat graham crackers, and no one ever knows it. The only thing that's not low fat is the icing.
Mix cold milk, instant pudding together, fold in container of cool whip.
Line 9X13 pan with graham crackers, (breaking piece when necessary to cover bottom of pan. Pour 1/2 of pudding mixture over crackers. Add another layer of graham crackers being sure to cover as much of pudding as possible. Add remaing 1/2 of pudding mixture. Add another layer of graham crackers. Spread can of chocolate frosting over last layer of graham crackers.