Add pudding mix and milk as package instructs and allow to set. Once thickened, fold in 8 oz cool whip or whipped cream.
Spray and 9”x9” pan with non-stick spray. Place a layer of graham crackers on the bottom. Start with whole sheets and fill in gaps with half or quarter sheets as necessary. You'll want enough graham crackers remaining to make 2 additional layers (3 total). , then top with ½ the pudding mix.
Top with ½ of the pudding mixture, and use a spatula or knife to spread evenly. Make sure all crackers are covered and fully coated.
Cover pudding with another layer of graham crackers, then top with remaining ½ of the pudding.
Add a final layer of graham crackers.