Stir in a teaspoon of lemon juice to the milk to make a buttermilk substitute and set aside. (you can use white vinegar instead of lemon juice)
Preheat your oven to 200°c (400ºf).
In a medium-size bowl whisk together the flour, baking powder and salt. Then add in the blueberries to the flour mixture and mix. Set aside.
In another bowl, add sugar, butter, vegetable oil, egg, and vanilla essence. Whisk for a few minutes until the mixture is well combined and slightly pale in color.
Now add in the flour mixture and the buttermilk substitute, then mix using folding motion until just combined, remember not to overmix the batter.
Line your muffin tin with 6 muffin liners. Spoon the batter evenly into the prepared muffin tin filling them almost to the top. Sprinkle the tops with little sugar.
Bake for about 20 minutes or until a toothpick inserted into the center of the muffins comes out clean.
Let the muffins cool slightly (about ten minutebefore removing from the tin. You can serve the muffins warm or completely cooled. Enjoy!
You can store the muffins in an airtight container for up to 3 days or freeze them in an air-tight container for up to 8 weeks.