Preheat your oven to 375°F (190°C). Line a muffin tin with paper liners or lightly grease the cups.
In a large bowl, cream together the softened butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition, then stir in the vanilla extract.
In a separate bowl, whisk together the flour, baking powder, and salt. Gradually add the dry ingredients to the wet mixture, alternating with the milk. Mix just until combined.
Gently fold in the blueberries.
Divide the batter evenly among the muffin cups, filling each about ⅔ full.
Bake for 20 minutes or until the tops are golden brown and a toothpick inserted in the center comes out clean.
Let the muffins cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.
Notes
Storing: Keep muffins in an airtight container at room temperature for up to 3 days.
Freezing: Freeze cooled muffins in a single layer on a baking sheet, then transfer to a freezer-safe container for up to 3 months.