Mix the Filling: In a large mixing bowl, whisk together the instant vanilla pudding mix and the cold whole milk until the mixture begins to thicken. Let it sit for about 3 minutes to set up slightly.

Fold in Whipped Topping: Gently fold the thawed whipped topping into the pudding mixture using a silicone spatula until completely combined and fluffy.

First Layer: Line the bottom of a 9x13 inch baking dish with a single layer of graham crackers. You may need to break a few crackers to fit them into the edges so the entire bottom is covered.

Second Layer: Spread exactly half of the pudding mixture evenly over the bottom layer of graham crackers.

Third Layer: Place another single layer of graham crackers evenly over the pudding mixture.

Fourth Layer: Spread the remaining half of the pudding mixture over the second layer of graham crackers.

Fifth Layer: Top with a final, third layer of graham crackers.

Add the Frosting: Remove the foil seal from the tub of store-bought chocolate frosting. Place the plastic tub in the microwave for 15 to 20 seconds, just until the frosting is slightly melted and easily pourable. Pour the melted frosting over the top layer of graham crackers and use a spatula to spread it into an even layer.

Chill: Cover the dish tightly with plastic wrap and place it in the refrigerator for at least 8 hours, or preferably overnight. This resting time is essential for the graham crackers to soften into a cake-like texture. Slice and serve cold!