Lightly grease a 9x13-inch baking dish with a thin swipe of butter or nonstick spray to keep the bottom graham cracker layer from sticking.
In a large bowl, whisk together the instant vanilla pudding mix and cold milk for 2–3 minutes, until thickened. Set aside for a few minutes to finish setting.
2 boxes (3.4 oz each) instant vanilla pudding mix, 3 cups cold whole milk
In a separate bowl, beat the softened cream cheese with a hand mixer or stand mixer until completely smooth and creamy, with no lumps. Scrape down the sides of the bowl as needed.
8 oz cream cheese
Add the thickened pudding to the cream cheese and beat again until the mixture is silky and fully blended.
2 boxes (3.4 oz each) instant vanilla pudding mix, 3 cups cold whole milk, 8 oz cream cheese
Gently fold the thawed whipped topping into the pudding mixture with a spatula until just combined. Do not beat; keep the mixture light and creamy.
8 oz whipped topping
Lay a single layer of graham crackers in the bottom of the prepared 9x13 pan, breaking pieces as needed to cover the bottom with minimal gaps.
2 sleeves honey graham crackers
Spoon half of the pudding mixture over the graham crackers and spread it gently into an even layer, smoothing it into the corners.
2 boxes (3.4 oz each) instant vanilla pudding mix, 3 cups cold whole milk, 8 oz cream cheese, 8 oz whipped topping
Place another single layer of graham crackers over the pudding, breaking pieces to fit snugly.
2 sleeves honey graham crackers
Spread the remaining pudding mixture evenly over the second graham cracker layer.
2 boxes (3.4 oz each) instant vanilla pudding mix, 3 cups cold whole milk, 8 oz cream cheese, 8 oz whipped topping
Add a final single layer of graham crackers over the pudding. This will sit directly under the chocolate ganache topping.
2 sleeves honey graham crackers
Place the heavy cream in a small saucepan over medium-low heat. Warm until steaming and just beginning to bubble around the edges; do not let it boil.
3/4 cup heavy cream
Add the chocolate chips to a heatproof bowl. Pour the hot cream over the chips, making sure they are mostly covered. Let stand for 2–3 minutes without stirring.
1 1/2 cups semi-sweet chocolate chips, 3/4 cup heavy cream
Add the butter and vanilla extract, then stir until the chocolate is completely melted and the mixture is smooth and glossy. If needed, microwave in 10-second bursts, stirring between each, until smooth.
1 1/2 cups semi-sweet chocolate chips, 3/4 cup heavy cream, 2 tablespoons unsalted butter, 1 teaspoon pure vanilla extract
Let the ganache sit for 5–7 minutes, until still pourable but not piping hot, so it doesn’t melt the top graham cracker layer.
Gently pour the ganache over the top graham cracker layer and use an offset spatula or the back of a spoon to spread it evenly to the edges.
Cover the pan tightly with plastic wrap or a lid and refrigerate for at least 6 hours, preferably overnight (8–12 hours), until the graham crackers have softened and the layers are set.
For clean slices, run a sharp knife under hot water, wipe it dry, and cut the cake into squares. Garnish with shaved chocolate, crushed graham crackers, fresh berries, or a light sprinkle of flaky sea salt if desired.
Shaved chocolate or chocolate curls, Crushed graham crackers, Fresh berries, Flaky sea salt