Prepare Dry Ingredients: In a large mixing bowl, whisk together the flour, baking powder, sugar, and salt.
Mix Wet Ingredients: In a separate bowl, whisk together the milk, eggs, melted butter, and vanilla extract (if using).
Combine Ingredients: Pour the wet ingredients into the dry ingredients. Stir gently with a whisk until just combined. Be careful not to overmix; a few lumps are fine. Let the batter rest for 5-10 minutes.
Preheat the Pan: Heat your cast iron skillet or non-stick griddle over medium heat. Use the water droplet test to check if the pan is ready: Drop a few water droplets on the surface. If they sizzle and dance, the pan is hot enough.
Cook the Pancakes: Lightly grease the skillet with butter. Pour ¼ cup of pancake batter onto the pan for each pancake. Cook for 2-3 minutes on the first side, or until small bubbles form and the edges start to look dry.
Flip and Finish Cooking: Flip the pancakes and cook for another 1-2 minutes, or until golden-brown and cooked through. Adjust the heat as needed to avoid burning.
Serve: Stack the pancakes on a plate and serve with syrup, fruit, or your favorite toppings.