1. Preheat oven to 350°.
2. Coat a 9-inch square metal baking pan with cooking spray. Combine 2 tablespoons sugar and cinnamon in a small bowl.
3. Combine butter and next 6 ingredients (through egg white) in a medium bowl, stirring with a whisk until blended. Gradually add 1 cup sugar, stirring with a whisk until blended. Stir in milk.
4. Weigh or lightly spoon 1 1/4 cups flour into dry measuring cups; level with a knife. Combine 1 1/4 cups flour, baking powder, and salt in a large bowl, stirring with a whisk.
5. Add milk mixture to flour mixture, stirring just until moist. Toss blueberries in 1/4 cup flour; fold into milk-flour mixture. Spoon batter into prepared pan. Sprinkle cinnamon-sugar mixture over top of batter. Bake at 350° for 35 minutes or until a wooden pick inserted in center comes out clean. Cool completely in pan on a wire rack.