Prepare the Dish and Ingredients: Set out a 9 x 13-inch (23 x 33 cm) baking dish. Make sure the cream cheese is softened, but keep the heavy cream cold until it is time to whip it.

Make the Lemon Cream Cheese Base: Place the softened cream cheese, lemon curd, powdered sugar, 1 tablespoon lemon zest, lemon juice, vanilla, and salt in a large mixing bowl. Beat on medium speed for 1 to 2 minutes, scraping the bowl as needed, until completely smooth. The mixture should look thick and glossy, without visible cream cheese lumps.

Whip the Cream: Pour the cold heavy cream into a separate clean bowl. Beat on medium-high speed until medium peaks form, about 2 to 4 minutes. When the beaters are lifted, the peaks should hold their shape while the tips bend slightly. Stop before the cream becomes stiff or grainy.

Lighten the Lemon Mixture: Fold about one-third of the whipped cream into the lemon cream cheese mixture. This first addition loosens the base and makes the remaining cream easier to incorporate.

Finish the Filling: Gently fold in the remaining whipped cream in two additions. Use broad strokes and rotate the bowl as you work. The finished filling should be smooth, fluffy, and thick enough to hold soft ridges.

Build the First Cracker Layer: Arrange 8 graham cracker sheets in a single layer across the bottom of the baking dish. Break or trim crackers as needed to cover the surface with minimal gaps.

Add the First Filling Layer: Spread one-third of the lemon filling, about 2 cups, evenly over the crackers. Use an offset spatula or the back of a spoon, taking care not to shift the bottom layer.

Repeat the Layers: Add another layer of 8 graham cracker sheets, followed by half of the remaining lemon filling. Repeat with the final 8 graham cracker sheets and the remaining filling.

Smooth and Garnish: Smooth the top into an even layer. Sprinkle with the optional lemon zest and crushed graham cracker crumbs, if using.

Cover and Chill: Cover the dish tightly without pressing the plastic wrap directly into the filling. Refrigerate for at least 8 hours, preferably overnight. The crackers should become uniformly soft and the filling should feel firm enough to slice.

Rest Before Cutting: Remove the cake from the refrigerator and let it stand for 15 minutes. This brief rest softens the filling slightly and makes the flavor more pronounced.

Slice and Serve: Cut the cake into 12 portions with a sharp knife. Wipe the knife between cuts for cleaner layers. Serve chilled.

[lovebox]: For best results, use softened cream cheese to prevent lumps in the filling. Keep the heavy cream cold for proper whipping.

[/lovebox]: Tips for Success

Use softened cream cheese to prevent small lumps in the lemon filling.

Keep the heavy cream cold and use a clean, grease-free bowl so it whips properly.

Do not overwhip the cream: Grainy or very stiff cream is harder to fold and can make the filling uneven.

Cover the entire surface with crackers, breaking them into smaller pieces to fill gaps along the edges.

Chill the cake for the full 8 hours. A shorter chill can leave the center crackers crisp and make the slices slide apart.

Add the crumb garnish shortly before serving when a drier, more distinct topping is preferred.