1. Preheat oven to 350. Line a 13 x 9 inch baking pan with foil, extending foil over edges of pan; set aside
2. In small pan, mix the 2 Tbsp. sugar and the cornstarch. Stir in blueberries and orange juice. Cook and stir over medium heat til thickened and bubbly. Remove from heat; set aside
3. For crust, in large bowl, stir together the 2 cups flour and the powdered sugar. Cut in butter til fine crumbs form and mixture starts to cling together. Mixture will be crumbly. Pat mixture firmly into prepared pan. Bake for 20 minutes.
4. Meanwhile, in medium bowl, beat cream cheese, the ½ cup sugar and the 1 Tbsp. flour with mixer on medium speed til smooth. Beat in eggs and vanilla til mixed. Pour over hot baked crust, spreading evenly. Spoon blueberry mixture in small mounds over cream cheese layer. Use a thin metal spatula or table knife to marble the mixture together.
5. Bake for 20 minutes more or til center is set. Remove and cool in pan on wire rack for 1 hour. Cover and chill for at least 1 hour. Using edges of foil lift uncut bars out of pan. Cut into squares. Store in airtight container in refrigerator for up to2 days. If desired sift with powdered sugar just before serving. To soften cream cheese quickly, unwrap cheese and put in on a plate. Microwave on 100 percent power for up to 30 seconds or til soft.