Mix together the wet ingredients followed by the dry. Stir in the blueberries last. In a muffin tin put in 12-15 liners and spray with cooking spray. Fill each muffin liner to the top with batter. Sprinkle the top of the batter with sugar. Cook at 425 for 8 minutes and then, without opening the over door, turn the oven to 350 and make for 12 additional minutes.