Line 9 x 13 pan with whole graham crackers (bottom only). Mix the instant pudding using the 3 cups of milk. Fold in the Cool Whip. Alternate layers of whole graham crackers with the pudding mixture (crackers, pudding, crackers, pudding, and final layer is crackers). Ice the top layer of graham crackers with the chocolate frosting. This may be done by icing the crackers individually before laying on pudding, then filling in the spaces with the remaining icing. Let set overnight.
