Preheat the oven to 375°F (190°C). Line a 12-cup muffin tin with paper liners or spray with non-stick spray.
In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.
In a large bowl, beat the butter and sugar together until light and fluffy (about 2-3 minutes).
Add eggs one at a time, mixing well after each addition. Then mix in the vanilla extract.
Alternate adding the dry ingredients and milk, stirring just until combined. Be careful not to overmix.
Gently fold in the blueberries and lemon zest (if using).
Spoon the batter into the muffin tin, filling each cup about 3/4 full. Top with coarse sugar if desired.
Bake for 20-25 minutes or until golden brown and a toothpick inserted into the center comes out clean.
Let the muffins cool in the tin for 5 minutes before transferring to a wire rack to cool completely.