Line 12 muffin 2 ½ inch muffin cups in a muffin baking pan with paper liners.
In a medium mixing bowl combine the flour, sugar, baking powder, and salt. Make a well in the center of the mixture and set aside.
In another mixing bowl combine the egg, milk, and melted butter. Add the egg mixture into the well of the dry ingredients and stir just until it forms a moist lumpy batter.
Fold in the blueberries.
Spoon the batter into the prepared muffin tins, filling each 3/4 of the way full.