Mix cream cheese, powdered sugar, and one cup of the heavy cream. BEAT WELL.
Add the vanilla, lemon zest, and the remaining heavy cream. Beat until soft peaks form.
In a 9×9 baking dish put a layer of graham crackers on the bottom. Add a layer of the cream cheese mixture.
Add a layer of the fruit mix and nuts. Repeat these steps until all the mixture is used.
Cover and let sit in the refrigerator overnight.
Summer squash and zucchini