For the crust: Preheat oven to 350˚F. Combine graham cracker crumbs, sugar and butter in a bowl. Press into a 10-inch tart pan with removable bottom. Bake for 10 minutes. Let cool completely before filling.
For the filling: Beat the Ricotta, powdered sugar, lemon juice, vanilla and lemon zest in a bowl until light and fluffy. Slowly add the heavy whipping cream and beat until thickened and increased in volume, about 4-5 minutes.
Pour filling into prepared crust and smooth out with an offset spatula. Refrigerate tart for at least 4 hours, overnight for best results. Top with fresh berries. Remove tart from pan and place on serving plate. Cut and serve cold.