Heat oven to 350℉/177℃.
Line muffin tin with baking cups or spray with baking spray. Set aside.
In a large bowl, whisk together flour, sugar, baking powder, and salt. Set aside.
In a medium bowl, whisk together vegetable oil, butter, egg, milk, and vanilla.
Pour over dry ingredients and mix together until wet ingredients are thoroughly incorporated.
Fold in blueberries
Scoop, or spoon, batter into prepared pan.
Bake for 20 minutes, or until lightly browned.