Preheat oven to 400 degrees F. Spray the baking sheet with non-stick cooking spray.
Mix flour, baking powder, baking soda, and salt with a fork in a medium bowl. Coarsely grate the cold butter into the dry ingredients and mix to blend evenly. Stir in blueberries, then buttermilk, and mix to combine.
Drop dough into rounds, place on baking sheet; sprinkle with sugar. Bake until golden brown about 12 minutes. Serve warm!