Preheat oven to 350 degrees F. Line a 13x9x2-inch baking pan with foil, extending foil over edges of pan; set pan aside.
In a small saucepan stir together the 2 tablespoons granulated sugar and the cornstarch. Stir in blueberries and orange juice. Cook and stir over medium heat until thickened and bubbly. Remove from heat and set aside.
For crust, in a large mixing bowl stir together the 2 cups flour and the powdered sugar. Cut in butter until fine crumbs form and mixture starts to cling together (mixture will still be crumbly). Pat mixture firmly into prepared pan. Bake for 20 minutes.
Meanwhile, in a medium bowl beat cream cheese, the 1/2 cup granulated sugar, and the 1 tablespoon flour until smooth. Beat in eggs and vanilla until combined. Pour over hot baked crust, spreading evenly. Spoon blueberry mixture in small mounds over the cheese layer. Use a thin metal spatula or table knife to marble the mixtures together.
Bake for 20 minutes more or until center is set. Cool in pan on a wire rack for 1 hour. Cover and chill at least 1 hour. Remove uncut bars from pan by lifting foil. Cut into bars. Store in an airtight container in the refrigerator up to 2 days. if desired, sift powdered sugar over bars just before serving.