Sift together flour, baking powder, salt and sugar in a large bowl.
Whisk in melted butter, egg and milk until combined. Let batter rest for 5 minutes.
Preheat a large frying pan over medium-high heat. Spray with cooking spray. Pour batter into the hot frying pan, about 1/4 cup of batter for each pancake. Cook for 2 to 3 minutes, until bubbles appear on the sides and centre of each pancake. Flip and cook until golden, about 1 to 2 minutes.