In a large bowl, whisk together flour, sugar, baking powder, and salt.
In another bowl, mix milk, egg, and melted butter until combined.
Pour the wet ingredients into the dry ingredients and stir until just combined.
Let the batter rest for about 5 minutes.
Heat a non-stick skillet over medium heat and lightly grease it.
Pour 1/4 cup of batter onto the skillet for each pancake.
Cook until bubbles form on the surface, about 2-3 minutes.
Flip the pancakes and cook for another 2-3 minutes until golden brown.
Transfer pancakes to a warm plate and cover with a towel.
Repeat with remaining batter, adjusting heat as necessary.