Prepare according to package directions, the 2 packages of pudding mix with milk. Fold in entire container of whipped topping.
Spray a 9x13-inch cake pan with non-stick cooking spray. Line bottom of pan with whole graham crackers. Put half of pudding mixture on top of crackers and spread evenly. Place another row of graham crackers evenly on top of pudding mixture, completely covering the pudding. Put the remainder of the pudding mixture on and spread evenly. Cover the pudding with more graham crackers, making sure there are no spaces in between the crackers.
Put frosting in microwave for 30 seconds to soften it. With a spatula, spread frosting on top of crackers. Refrigerate for 1 hour until frosting hardens. Cover with plastic wrap and keep refrigerated 12 to 24 hours before serving. This will soften the crackers. Cut in squares and serve.
Variation: Make with chocolate fudge instant pudding and chocolate grahams. The chocolate graham crackers usually have sugar on top and you need to turn the top row upside down to make it easier to spread the frosting.