Lightly spray a 9×13-inch baking dish with nonstick cooking spray.
Add the instant chocolate pudding mixes and cold whole milk to a large mixing bowl. Whisk for about two minutes or until smooth and beginning to thicken.
Add the vanilla extract and sea salt. Whisk until combined, then allow the pudding to stand for five minutes.
Add the thawed whipped topping. Gently fold it into the pudding with a rubber spatula until the mixture is smooth and no large white streaks remain.
Arrange a single layer of graham crackers across the bottom of the prepared dish. Break crackers as needed to completely cover the bottom.
Spread half of the chocolate pudding mixture evenly over the graham crackers.
Add a second complete layer of graham crackers over the filling.
Spread the remaining chocolate filling over the second layer.
Finish with a third complete layer of graham crackers.
Place the semisweet chocolate chips and butter in a medium heat-safe bowl.
Heat the heavy cream for 45 to 60 seconds in the microwave or until hot and steaming. Pour the cream over the chocolate chips and butter.
Let the chocolate mixture stand untouched for two to three minutes. Stir until completely smooth.
Allow the ganache to cool for 10 to 15 minutes or until it is still pourable but only slightly warm.
Pour the ganache over the final layer of graham crackers and spread it evenly to the edges.
Add crushed graham cracker crumbs, mini chocolate chips, or chocolate curls, if desired.
Cover the baking dish tightly and refrigerate for at least eight hours, preferably overnight.
Cut into 12 pieces and serve chilled.