Preheat oven at 375F. Line the muffin tray with muffin liners.
Mix all the wet ingredients inn a bowl (oil, egg, milk, sugar and vanilla extract).
In another bowl, mix baking powder and all purpose flour. Now add the mixture of wet ingredients.
Add blueberries and fold the batter (do not over mix). You can crush half of the blueberries with the fork and add half of the whole blueberries.
Add 2 tablespoon of batter in each muffin lined tin. Sprinkle some sugar on top.
Bake at 375F for 30 minutes or until a clean toothpick comes out from the centre of the muffin.
Remove muffins from the tin and cool for 30 minutes.