Chocolate eclair cake

2 (3 ounce) packages instant vanilla pudding mix 

 3 cups milk 

 1 (8 ounce) container frozen whipped topping, thawed 

 1 (16 ounce) package graham crackers

 1/4 cup milk 

 1/3 cup unsweetened cocoa powder 

 1 cup white sugar 

 2 tablespoons butter 

 1 teaspoon vanilla extract 

 Directions In a large bowl, combine pudding mix and 3 cups milk; mix well. Fold in whipped topping and beat with mixer for 2 minutes. In a buttered 9x13 inch baking dish, spread a layer of graham crackers on the bottom of the dish. Spread 1/2 of the pudding mixture over crackers, then top with graham crackers. Spread remaining pudding over crackers; top second pudding layer with another layer of crackers. 

 To make topping: In a medium saucepan over medium-high heat, combine 1/4 cup milk, cocoa and sugar and allow to boil for 1 minute; remove from heat and add butter and vanilla. Mix well and cool. Pour sauce over graham cracker layer and refrigerate until set; serve.