Combine flour, sugar, baking powder, baking soda, and salt in a large bowl and mix together. Set aside.
Whisk egg and butter into the milk mixture and mix together. Add flour mixture and whisk until lumps are gone. Let batter set for 10 minutes.
Heat skillet to medium heat and spray with cooking spray. Pour ¼ cups of the batter onto the skillet and cook until bubbles appear on the top (2-3 minutes). Flip with a spatula and cook the other side until browned.
Video
Notes
If you don't have buttermilk, add ¾ tablespoon of vinegar or lemon juice to the milk and let it "sour" for 5 minutes.