In a large bowl, whisk together flour, baking powder, salt, and sugar.
Make a well in the center. Add milk, egg, melted butter, and vanilla if using.
Whisk the egg, then gently mix wet and dry ingredients until just combined; batter should be thick and a little lumpy.
Preheat a non-stick skillet or griddle over medium-high heat. Grease with butter, oil, or spray.
Pour ¼ cup batter for each pancake. Cook until bubbles form and edges look set, about 2 minutes. Flip and cook 1 minute more.
Serve warm with your favorite toppings.
