In a large mixing bowl, whisk together the instant vanilla pudding mix and cold milk for about 2 minutes, or until thickened.
Gently fold in the whipped topping until well combined.
In a 9x13-inch baking dish, arrange a layer of graham crackers on the bottom.
Spread half of the pudding mixture over the graham crackers.
Repeat with another layer of graham crackers and the remaining pudding mixture.
Top with a final layer of graham crackers.
Spread the chocolate frosting evenly over the top layer of graham crackers.
Cover the dish with plastic wrap and refrigerate for at least 4 hours, or overnight for best results.
Cut into squares and serve chilled.