Some folks make this with whole crackers, but I prefer to crush the whole box of graham crackers and then mix in 1 stick of melted butter to make the crusts.
In a large bowl, combine the milk and vanilla pudding. Fold in the whipped topping thoroughly.
Spray a 9x13 baking dish
Line the bottom of the dish with 1/3 of the graham crackers, pressing them firmly onto the bottom of the dish.
Put half of the pudding mix in the dish over the crushed graham crackers and level it off.
Put another 1/3 of the graham crackers over the pudding.
Put the other half of the pudding over the graham crackers and level it off.
Put the final 1/3 of the graham crackers over the top of the pudding.
To make the chocolate frosting, combine the ingredients and microwave for 1-2 minutes, whisking every 30 seconds until smooth. Let cool for 10 minutes and then pour and smooth over the top.
OR, warm the tub of chocolate frosting, uncovered, in the microwave for 1 minute on half power. Pour over the top of the dessert.
Refrigerate for at least 12 hours before serving. Freezing for 1 hour before cutting will make that much easier to do.
For an alternative dessert, you can replace the graham crackers with vanilla wafers, replace the vanilla pudding with banana pudding, and then add a thin slice a ripe banana into to the pudding mix.