In a stand mixer with a whisk attachment or using a hand mixer in a large bowl, combine the heavy cream, powdered sugar, and vanilla extract. Start at a low speed, gradually increasing to high, and beat until stiff peaks form. Be careful not to overwhip.

Spread a thin layer of the whipped cream evenly across the bottom of a 9x13-inch baking pan or casserole dish. This helps anchor the first layer of graham crackers.

Arrange a single layer of chocolate graham crackers or wafers over the whipped cream, trimming the crackers as necessary to ensure full coverage.

Divide the remaining whipped cream into four equal portions. Spread one portion over the cracker layer, smoothing it evenly.

Add another layer of graham crackers over the whipped cream, followed by another layer of whipped cream.

Repeat this layering process two more times, ending with a final layer of whipped cream on top.

Sprinkle crushed chocolate graham crackers, chocolate wafers, or shaved chocolate over the top as a garnish.

Cover the dish and refrigerate for at least 5 hours or overnight. This allows the crackers to soften and meld with the cream, creating a cake-like texture.

Once set, slice into squares and serve chilled directly from the dish.