Combine sugar, egg, vegetable oil, milk, and vanilla in the bowl of a stand mixer. In a medium bowl, whisk together flour, bakign powder, and salt. Add dry mixture to wet mixture and mix until the lumps are gone but just barely. Add sour cream and stir in with a rubber spatula.

Reserve some blueberries to press on top of the muffins and place the rest in the batter. Stir in blueberries.

Place cupcake liners in a muffin tin and fill evenly with batter. You can fill the cupcake liners full of batter. I like to do this with an ice cream scoop. Add extra blueberries to the top, if desired. Bake 20-25 minutes at 375°.