Combine the flour, sugar, baking powder, and salt in a mixing bowl. Add the egg, milk, butter, lemon juice, and zest.

Stir to combine–the batter should be lumpy. Don’t mix it too hard. Muffin batter doesn’t like that. Gently fold in blueberries. Lightly grease muffin cups or use paper liners. Fill each cup about 2/3 to 3/4 full. This should make 12 muffins. Sprinkle extra sugar and lemon zest on the tops.

Bake at 400-degrees for about 20 minutes or until golden.