Preheat the oven to 425°F (218°C). Line a 12-cup muffin tin with paper liners or lightly grease.
In a large bowl, whisk together the flour, sugar, baking powder, and salt.
In a separate bowl, whisk the milk, vegetable oil, egg, and vanilla until smooth.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Gently fold in the blueberries.
Divide the batter into the muffin cups, filling each about ¾ to full.
Bake at 425°F for 5 minutes, then reduce the temperature to 350°F (177°C) and bake for 18–20 minutes, or until a toothpick inserted in the center comes out clean.
Cool in the pan for 5 minutes, then transfer to a wire rack.