Preheat and prep – Heat a skillet over medium heat or a griddle to 350°F. Lightly grease with butter.
Mix dry ingredients – In a large mixing bowl, whisk together flour, baking powder, baking soda, sugar, and salt.
Combine wet ingredients – In another bowl, whisk together the milk, egg, melted butter, and vanilla extract.
Make the batter – Pour the wet ingredients into the dry ingredients and gently mix until just combined. Lumps are okay! Overmixing will make the pancakes tough.
Let it rest – Let the batter sit for 5 minutes to help activate the baking powder.
Cook the pancakes – Use a 1/4 cup measuring cup to pour batter onto the hot skillet. Cook until bubbles form on the surface (about 2-3 minutes), then flip.
Flip and finish – Cook the other side for another 1-2 minutes until golden and cooked through. Transfer to a baking sheet and keep warm in a low oven if needed.