Step 1: Make the Filling

In a large bowl, whisk together the pudding mix and cold milk until smooth.

Let it sit for 5 minutes until it thickens.

Gently fold in the Cool Whip (or whipped cream) until fully combined.

Step 2: Assemble the Cake

In a 9×13-inch baking dish, lay down a single layer of graham crackers (breaking them as needed to fit).

Spread half of the pudding mixture over the crackers.

Add another layer of graham crackers, then spread the remaining pudding mixture on top.

Finish with a final layer of graham crackers on top.

Step 3: Make the Chocolate Topping

In a small saucepan or microwave-safe bowl, heat the heavy cream until hot (not boiling).

Pour over the chocolate chips and let sit for 1 minute.

Stir until smooth, then mix in vanilla extract and corn syrup (if using).

Step 4: Finish & Chill

Pour the chocolate topping evenly over the top layer of graham crackers.

Cover and chill in the refrigerator for at least 6 hours (or overnight) to soften the crackers and let flavors meld.

Step 5: Serve & Enjoy!

Slice into squares and serve chilled.

For extra flair, garnish with whipped cream, chocolate shavings, or fresh berries!