2 (3.5 ounce) packages instant vanilla pudding mix
1 (8 ounce) container frozen whipped topping, thawed
3 cups milk
1 (16 ounce) package graham cracker squares
1 (16 ounce) package prepared chocolate frosting
Stir pudding mix, whipped topping, and milk together in a medium bowl until well blended.
Arrange a single layer of graham cracker squares in the bottom of a 13×9 inch baking pan. Evenly spread half of the pudding mixture over the crackers. Top with another layer of crackers and the remaining pudding mixture. Top with a final layer of graham crackers.
Spread the frosting over the whole cake up to the edges of the pan. Cover, and chill at least 4 hours before serving.