1. Layer the bottom of a 13x9 pan with graham crackers.
2. Mix pudding and cool for 10 mins.
3. Add cool whip to pudding and mix well.
4. Pour 1/2 of mixture over graham crackers. Put another layer of graham crackers over pudding mixture.
5. Pour the rest of pudding mixture over graham crackers, then put one more layer of graham crackers over pudding mixture. ( You should have 3 layers of graham crackers with 2 layers o pudding mixture between.)
6. Mix sugar, cocoa, salt, and milk and heat to boiling. Be careful not to burn. Stir constantly.
7. Add butter and vanilla and stir until melted with heat turned down to low.
8. Pour over graham crackers. Chill for several hours.