Preheat oven to 350 degrees F. Lightly grease an 8 x 8 inch pan with cooking spray.

In the bowl of a food processor (or in a medium mixing bowl if not using a food processor), lightly pulse the all-purpose flour, whole-wheat pastry flour, powdered sugar, ¼ teaspoon lemon zest, and salt. Add butter pieces and pulse just until mixture is crumbly and resembles coarse cornmeal. (If not using a food processor, cut butter pieces into the dry ingredients with a fork or pastry blender.) The mixture will feel dry to the touch. Press the mixture onto bottom of the prepared pan. Bake 20 to 22 minutes, until lightly browned. Set aside to cool for at least 15 minutes.

Meanwhile, in the bowl of a standing mixer fitted with the paddle attachment (or a large mixing bowl), beat together the cream cheese, Greek yogurt, and granulated sugar until smooth. Add the egg and beat just until blended. Mix in the fresh lemon juice, cornstarch, vanilla, and remaining ¼ teaspoon lemon zest. Beat well.

Spread preserves over the cooled shortbread. Pour the cream cheese mixture over preserves, spreading to edges. Bake an additional 28 to 32 minutes, or until the cheesecake appears set on top and only jiggles slightly when you wiggle the pan. Let cool on a wire rack for 1 hour. Cover and chill 4 to 8 hours. Cut into bars and garnish with whipped cream and fresh strawberry slices.