Preheat the oven to 350F. Spray a 8 by 8 inch baking dish with cooking spray. Set aside.

In a medium bowl, combine the graham cracker crumbs, melted butter, sugar, and lemon zest. Stir until graham cracker crumbs are moist. Press crumbs into the prepared pan, pressing the crust mixture one inch up the side of the pan. Bake for 10 minutes. Remove from oven and allow to cool to room temperature.

Once the crust is cool, combine the egg yolks and condensed milk until well mixed. Stir in the lemon juice and lemon zest. Stir until mixture begins to slightly thicken. Gently fold in the raspberries. Fold carefully so you don't break the raspberries.

Pour the lemon raspberry filling evenly over the graham cracker crust. Bake for 15 minutes, or until just set.

Cool to room temperature, then chill for at least one hour before serving. Cut into bars and serve. Keep bars in the refrigerator-up to five days.

*Note-use fresh raspberries and make sure you gently fold the berries into the lemon filling or you will have pink bars.