Sift together flour, 2 tablespoons sugar, baking powder, and salt. Make a well in the center. Combine egg, milk, and oil, and pour into well in the dry ingredients, stirring quickly just to moisten. Do not stir too much! Toss blueberries with remaining 2 tablespoons sugar and gently stir into batter. Fill greased muffin tins two-thirds full. Sprinkle tops with sugar. Bake for 20 to 25 minutes at 400 degrees F.