01 -
Whisk the pudding mix with 3 cups cold milk in a large bowl for about 2 minutes, until thickened.
02 -
Fold in the thawed whipped topping until the filling is smooth and evenly combined.
03 -
Arrange a single layer of graham crackers in the bottom of a 9x13-inch dish, breaking pieces as needed to cover the base.
04 -
Spread half of the pudding filling over the crackers. Add a second cracker layer, spread on the remaining filling, then top with a final layer of graham crackers.
05 -
Whisk sugar and cocoa powder in a medium saucepan. Whisk in 1/4 cup milk and cook over medium heat until it comes to a boil. Boil for 1 minute, then remove from heat.
06 -
Whisk butter and vanilla into the hot cocoa mixture until smooth and glossy. Pour over the top graham cracker layer and spread gently.
07 -
Refrigerate uncovered until the glaze cools, then cover and chill at least 8 hours or overnight. Garnish with chocolate curls if using and serve cold.