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Preheat oven to 350°.
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Lightly spoon flour into dry measuring cups; level with a knife. Combine flour, baking powder, soda, and salt, stirring with a whisk.
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Place granulated sugar and butter in a large bowl; beat with a mixer at medium speed until well blended (about 2 minutes).
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Add vanilla, egg, and egg white; beat well. Add flour mixture and buttermilk alternately to sugar mixture, beginning and ending with flour mixture; mix after each addition.
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Spoon half of the batter into a 9-inch round baking pan coated with cooking spray. Sprinkle evenly with 1 cup blueberries.
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Spoon remaining batter over the blueberries; sprinkle evenly with remaining 1 cup blueberries. Sprinkle the top evenly with 1 tablespoon turbinado sugar.
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Bake at 350° for 50 minutes or until a wooden pick inserted in center comes out clean.
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Cool in pan 10 minutes on a wire rack; remove from pan. Cool completely on wire rack.