1 1/3 cups whole-wheat flour
1/2 teaspoon baking powder
1/2 teaspoon baking soda
1/2 teaspoon salt
1 cup brown sugar
2 tablespoons butter -- softened
2 tablespoons vegetable oil
1 large egg
1 teaspoon vanilla
3 tablespoons whole-wheat flour
1/2 cup granulated sugar
2 tablespoons all-purpose flour
1 teaspoon grated lemon rind
2 cups blueberries -- picked clean
1 tablespoon emon juice

1. Preheat oven to 350 degrees. Spray 9 x 13 pan with pan spray.
2. Stir together 1 1/3 cup whole wheat flour, baking powder, soda & salt; set aside. In mixer beat together brown sugar, butter, oil, egg & vanilla until smooth, making sure no lumps of brown sugar remain. Add the dry ingredients & stir until well- blended; the mixture will be firm. Reserve 1/2 cup (packed) for topping.
3. Place remaining dough in pan & cover with a piece of plastic wrap & use it to press dough into the bottom of prepared pan. Remove plastic wrap; bake at 350 degrees for 15 minutes or until puffed & golden.
4. Using fingertips, gradually mix remaining 3 tablespoons flour into reserved 1/2 cup of topping until it gets crumbly. Set aside.
5. Combine sugar, all-purpose flour & zest; set aside. Combine blueberries & lemon juice in saucepan; cook stirring over medium heat until berries begin to exude juice. Add sugar mixture & stir until the filling reaches a simmer & thickens.
6. With a wooden spoon, push down the higher outside edges of the baked crust; pour hot filling over it & spread all the way to the sides of the dish. Spinkle with topping. Bake 15 to 20 minutes or until topping is golden.
7. Transfer to a rack & let cool, covered with a kitchen towel to soften crumbs slightly. Cut into 24 bars. Dust with confectioners' sugar & serve.