Preheat Your Oven: Preheat your oven to 375 degrees F. Adjust your oven rack to the middle position for even baking. Line a muffin tin with paper liners and lightly spray with nonstick cooking spray.
Prepare Dry Ingredients: In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.
Mix Wet Ingredients: In a large bowl, cream together the butter and sugar until light and fluffy. Add the eggs one at a time, beating well after each addition. Mix in the milk and vanilla extract until fully incorporated.
Combine Ingredients: Gradually add the dry ingredients to the wet mixture, mixing until just combined. Be careful not to over-mix, as this can result in tough muffins. Gently fold in the blueberries using a spatula or wooden spoon. The muffin batter will have a thick consistency.
Fill Muffin Cups: Evenly distribute the batter into the prepared muffin cups, filling each one to the top.