Preheat oven to 400°.
Grease a muffin tin with 12 muffin cups.
In a large bowl, stir together flour, sugar, baking powder, and salt.
In another bowl, stir together milk, butter, egg, and vanilla until blended.
Make a well in the center of the dry ingredients and add the liquid mixture, stirring just until combined.
Mash ¼ cup of blueberries and stir into batter with a few quick strokes.
Stir in remaining blueberries.
Spoon batter into prepared muffin tins, and using 1 Tablespoon of sugar, sprinkle the tops of all the muffins.
Bake at 400° for 20 minutes or until tester comes out clean.
Remove from oven and let cool in tins for 5 minutes before removing muffins to a wire rack.