In a mixing bowl, add the flour, sugar, baking powder, and salt. Mix until combined.
In a separate bowl, whisk together the oil, egg, milk, and vanilla extract.
Slowly add the wet ingredients into the dry, and then fold in the blueberries. Save a little to sprinkle on top if desired.
Sprinkle the top with course sugar if desired.
Divide the batter into 12 muffin liners and baker at 375° for 5 minutes, and then lower the oven temperature to 350° for 20 more minutes, until the muffins are golden brown.