Position rack in the middle of the oven. Preheat the oven to 375 degrees F (190 degrees C). Spray the top of a muffin pan with nonstick spray, and line with paper liners.
Cream together 1 1/4 cups sugar, butter, and salt in a large bowl until light and fluffy. Beat in eggs one at a time.
Mix together 1 3/4 cups flour and baking powder. Beat in the flour mixture alternately with the buttermilk into egg mixture, mixing just until incorporated.
Crush 1/4 of the blueberries, and stir into the batter. Mix the rest of the whole blueberries with the remaining 1/4 cup flour, and fold into the batter. Scoop into muffin cups. Sprinkle tops lightly with sugar.
Bake in the preheated oven until golden brown and tops spring back when lightly tapped, about 30 minutes.