Preheat your oven to 400°F (200°C). Grease a muffin tin or line with paper liners.
In a large bowl, whisk together the flour, sugar, salt, and baking powder.
In another bowl, mix the vegetable oil, egg, milk, and vanilla extract.
Pour the wet ingredients into the dry ingredients and stir until just combined. Do not overmix.
Gently fold in the blueberries.
Spoon the batter into the prepared muffin tin, filling each cup about ⅔ full.
Bake for 20 minutes, or until a toothpick inserted into the center comes out clean.
Let the muffins cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.