Mix pudding with milk. When firm, whisk in cool whip.
In large foil baking pan or casserole dish (9 x 13), layer whole graham crackers in bottom of pan, then cover with 1/2 of the pudding mix. Add another layer of grahams, then cover with the rest of the pudding mix. Finish with one more layer of grahams.
Melt frosting in it's container in the microwave (remove foil first) for approximately 45 seconds. Stir, then pour evenly over grahams.
Refrigerate over night.
(This recipe can be played with to make it however you like it. You can try different flavors of pudding mix, like white chocolate, banana, or cheesecake, or use chocolate grahams and chocolate pudding if you are a serious chocolate lover :)