In a large bowl whisk flour, sugar, baking powder and salt,
Use a measuring cup that holds at least 1 cup and add vegetable oil, egg and then fill the cup to the 1-cup line with milk (about 1/3 to a 1/2 cup of milk).
Add vanilla and whisk until combined.
Add milk mixture to the bowl with flour and sugar then use a fork to combine. Do not over mix. (The muffin batter will be pretty thick).
Add blueberries and use a spatula or spoon to gently fold the blueberries into the muffin batter.
Divide the batter between the muffin cups filling about ½ full.