- 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.