This doesn't seem like it would be as good as it is - but it's pretty spectacular. It's a great dessert to bring to a potluck.
2 (3.5 oz.) boxes vanilla instant pudding
3 cups milk
1 (8 oz.) container Cool Whip
1 (14.4 oz) box graham crackers
1/3 cup unsweetened cocoa powder
1 cup sugar
1/4 cup milk
1/2 cup butter
1 tsp. vanilla extract
Start by making the filling by combining the milk and pudding mix. Give it a minute to thicken, then add cool whip.
Place a layer of graham crackers in the bottom of a 9x13 dish (or 2 8x8 pans). You'll use a wrapped package for each layer. Spread half of the pudding mix on the graham crackers. Add second layer of graham crackers, add remaining pudding and add the last layer of graham crackers.
For the chocolate topping, bring cocoa, milk and sugar to a full rolling boil. Looking at the recipe it may not seem like there is enough liquid for that to happen, but it mixes up surprisingly well. Boil about one minute, stirring frequently. Remove from heat and cool one minute. Add butter and vanilla and stir until butter is melted.
Pour chocolate topping over the top layer of graham crackers. Spread evenly to coat. Refrigerate overnight and enjoy!