In a medium bowl, mix together 2 (3.5 ounce) packages instant vanilla pudding mix, 3 cups milk and 8 ounce tub whipped topping, thawed.
In an 9x13-inch baking dish, arrange a single layer of the 2 sleeves graham cracker squares on the bottom. You may have to break them up a bit to get enough crackers to cover the bottom of your dish.
Spread half of the pudding mixture on top of the crackers.
Layer another layer of graham crackers over the pudding mixture.
Then layer the other half of the pudding mixture on top of crackers.
Top with a final layer of graham crackers.
Put plastic wrap over dish and put in fridge for about 30 min to an hour to allow pudding to set.
When ready, put the 16 ounce container chocolate frosting (with the top removed) in the microwave for about 15 seconds to soften (remove lid and aluminum foil top before microwaving).
Take out and stir frosting. It should be easily spreadable now.
Remove plastic wrap from dish and evenly spread chocolate frosting all over the top layer of graham crackers.
Place plastic wrap over top of dish and put back in fridge and let it chill overnight.
This dessert gets better over time. The graham crackers need plenty of time to soften up.
When ready, slice and serve!
You must use INSTANT pudding so be very careful when purchasing. The instant pudding is right near the cook and serve pudding. The cook and serve pudding will not work in this recipe.
This dessert does not take long to prepare but it definitely needs lots of time to set up. Make this the night before you actually need to serve it. Try using chocolate graham crackers with white chocolate pudding!
UPDATE: Since first sharing this recipe in 2011, it appears different brands put different amounts of graham crackers in each sleeve. Some brands are also making smaller sleeves so you don't have to open a whole full sleeve. And some brands are also getting cheap and putting less graham crackers in a box. So, it is possible you will need more graham crackers than what I stated above. Be prepared to potentially use the entire box you purchased.