Chocolate Eclair Cake

I got this recipe from my friend Karen. It is fantastic!

graham crackers (regular or chocolate)
vanilla instant pudding mix
9 oz Cool Whip
1 cup sugar
1/2 cup cocoa powder
1 can evaporated milk
1 stick butter
1 tsp vanilla

Line a "Pammed" 9x13 pan with whole graham crackers.
Mix vanilla instant pudding according to directions. Fold in all the Cool Whip.
Layer pudding mixture with graham crackers (3 cracker layers & 2 pudding layers) Begin and end with graham crackers.

Combine 1 cup sugar, 1/2 cup cocoa and almost the whole can of evaporated milk. Heat on medium, stir constantly bring to a boil for exactly 1 minute. Remove from heat and add 1 stick butter and 2 tsp vanilla. Stir until combined. Pour over cake and refrigerate overnight.