Preheat the oven to 375?F (190?C) and grease the muffin tin.

In a mixing bowl, whisk together the flour, baking powder, salt, and sugar.

In another bowl, combine the milk, beaten egg, and melted butter.

Pour the wet ingredients into the dry ingredients and stir until just combined.

Spoon the batter into the prepared muffin tin, filling each cup about 2/3 full.

Bake for 15-20 minutes or until a toothpick inserted into the center comes out clean.

Let the muffins cool in the tin for a few minutes before transferring to a wire rack.