Stir: Stir together flour, baking powder, sugar, and salt in a large bowl. In a separate bowl whisk milk, egg, melted butter, and vanilla. Add milk mixture to the dry ingredients, stirring until mostly combined (some lumps in the batter is okay, do not over stir).
Cook: Lightly grease a large saute pan and set over medium heat. Spoon ¼ cup portions of pancake batter into the pan, cooking until you see bubbles form on top and bottom is golden brown. Flip and continue cooking until golden brown.
Serve: Set oven to 200°F (95°C). Keep cooked pancakes warm by setting on an oven-safe baking sheet and placing in the oven.