Preheat oven to 325 degrees F and place the rack in the center of the oven. Have ready a 9 x 13 x 2 inch baking pan lined with aluminum foil across the bottom and up two opposite sides of the pan. Spray the foil with a non stick cooking spray.
Graham Cracker Crust: In a small bowl combine the graham cracker crumbs, sugar, and melted butter. Press mixture evenly over the bottom of the prepared pan. Bake in preheated oven for 10 minutes. Set aside to cool.
Increase the oven temperature to 350 degrees .
Cheesecake Filling: In the bowl of electric mixer, or with a hand mixer, beat the cream cheese until smooth. Add the sugar, lemon juice,and vanilla extract and beat until smooth. Add the eggs, one at a time, beating until smooth. Scrape down the sides of the bowl, as needed. Pour the cheesecake filling over the graham cracker base and bake for about 18 - 20 minutes or until the cheesecake batter is just set.
Remove from oven and place on a wire rack to cool. Cover and place in the refrigerator for several hours to make the squares easier to cut. To cut into squares - place on a cutting board, remove the foil, and with a sharp knife, cut into 2 inch squares. Have a damp cloth on hand to wipe the knife between cuts.Store leftovers in the refrigerator.