Mix pudding mix and 3 cups milk. Beat as the directions indicate.
Fold in the thawed whipped topping.
Line a 9x13 pan with a layer of graham crackers. Pour 1/3 of pudding mix over crackers. Repeat 2 more times. Top with a final layer of graham crackers. Break crackers as needed to fill in the spaces.
Remove lid and foil liner from frosting. Put in the microwave for about a minute to soften. You want this so it is pourable. Stir to blend and pour over final layer of graham crackers. Refirgerate for several hours or overnight. Cut into squares of desired size and serve.
I have made this with chocolate grahams, butterscotch pudding, and sprinkled Heath chips on each layer. I have also added fresh, cut strawberries to each layer with the vanila pudding.