1. Butter the bottom of a 9x13 inch pan. Place a layer of graham crackers on bottom. Mix the pudding mix with milk. Beat on medium speed until well blended well, about 2 minute. 2. Fold in the cool whip. Pour 1/2 mixture over the crackers. Cover with more crackers and pour the remainder of the pudding on top of that. 3. To make icing: mix all ingredients and spread over the cake. 4. Refrigerate for 24 hrs then serve.