In a food processor, pulse the graham crackers until fine crumbs form (or place them in a gallon size baggie and pound with a rolling pin).
Add the sugar and pulse again (or stir) until combined. Add the melted butter and pulse or stir until crumbs are evenly moistened.
Line a 24-cup mini muffin pan with plastic wrap (use two sheets, placed crosswise across the tin, as pictured). Place a heaping tablespoon of graham cracker crumbs in each cavity and press onto bottom and sides with your fingers.
Transfer to freezer to chill for 15-20 minutes while you make the filling. Gently lift the plastic wrap to remove the tart shells from the pan.
In a medium bowl, beat together the cream cheese, lemon juice, and sugar.
In a separate medium bowl, whip the whipping cream and vanilla to soft peaks. Fold the whipped cream into the cream cheese mixture until combined
Spoon a dollop of filling into each tart shell and garnish with fruit as desired.