Coat a 9-inch square metal baking pan with cooking spray.
Combine 2 tablespoons sugar and cinnamon in a small bowl.
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.
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.
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.