Cover the bottom of a 9×13 baking dish with graham crackers, breaking them to fit if necessary.

Add the pudding mix to a large bowl, and pour in the milk. Whisk until smooth.

Fold in the thawed whipped topping.

Spread half of the pudding mixture evenly over the layer of crackers.

Add another layer of graham crackers on top of the filling.

Spread the remaining pudding mixture on top of that second layer of crackers.

Top with the last layer of graham crackers.

Add the chocolate chips, heavy cream, corn syrup, and vanilla extract to a medium-sized microwave-safe bowl.

Heat for 1 minute, stir. Continue cooking for 30 seconds at a time, stirring after each round of heating, until chocolate chips are almost melted.

Remove and stir until smooth.

Pour the melted chocolate mixture over the graham crackers, and spread evenly with an offset spatula.

Cover and place it in the refrigerator for at least 8 hours, overnight is best.

Cut and serve with additional whipped cream and berries, if desired.