In a medium bowl, whisk together flour, sugar, baking powder, baking soda, and salt until well combined.
In another bowl, whisk milk, egg, melted butter (or oil), and vanilla until smooth.
Pour the wet ingredients into the dry ingredients. Stir just until combined; a few lumps are perfectly fine.
Let the batter rest for 5 minutes if you have time. If not, no big deal—the pancakes still win.
Heat a nonstick skillet or griddle over medium heat and lightly coat with butter or oil.
Pour about 1/4 cup of batter for each pancake. Cook until bubbles form on the surface and the edges look set, about 2–3 minutes.
Flip carefully and cook another 1–2 minutes on the other side until golden brown.
Transfer to a plate and repeat with the remaining batter. Keep stacks warm if you like, or serve immediately.