In a large mixing bowl, whip the heavy cream until soft peaks form.

In another bowl, combine the softened cream cheese, powdered sugar, lemon curd, and vanilla extract. Beat until smooth and well combined.

Gently fold the whipped cream into the lemon mixture until fully combined and fluffy.

In a 9x13-inch baking dish, arrange a layer of graham crackers on the bottom.

Spread half of the lemon filling over the layer of cookies.

Add another layer of graham crackers, followed by the remaining lemon filling. Top with a final layer of graham crackers.

Cover the dish with plastic wrap and refrigerate for at least 4 hours, or overnight if possible.

Before serving, garnish with lemon zest and fresh lemon slices if desired.

Cut into squares and serve chilled.