Heat your oven to 375 degrees F. Prepare your muffin tins with liners.
In a large bowl ceam the butter with the lemon zest and sugar. Make sure the you beat this until it becomes fluffy.
Add the egg and vanilla to this mixutre. Beat until combined.
In a small bowl cover the blueberries with 1/4 cup of flour. This will help the blueberries from sinking to the bottom of your muffins.
In a medium bowl whisk together the rest of the flour, baking powder, and salt.
In small portions alternate adding the dry ingredients and milk into the butter mixture.
Once everything is well combined (don't overmix) fold in the blueberries.
Pour your batter evenly into the muffin tin. I like to use a cookie scoop for this. Sprinkle sugar on the top if you prefer (this is optional). Bake the muffins for 25-30 minutes or until a toothpick inserted in the center comes out clean.
Let your muffins cool in the muffin tin for 5-10 minutes before taking them out to cool on a wire rack.