In a large bowl, whisk together flour, baking powder, salt, and sugar until well combined.

Make a well in the center. Add milk, egg, melted butter, and vanilla (if using). Gently whisk until just combined. The batter will be lumpy.

Heat a non-stick griddle or skillet over medium heat. Lightly grease with butter or oil.

Scoop about ¼ cup of batter onto the griddle for each pancake. Let cook for 2–3 minutes, or until bubbles form on the surface and the edges look set.

Flip and cook for another 1–2 minutes, until golden. Transfer to a plate and cover loosely with foil to keep warm while you finish the batch.