In a small bowl, sift together the flour, sugar, baking powder, and salt. Set aside.
In a separate mixing bowl, whisk the egg yolks, milk, melted butter, and vanilla extract together until combined.
Gradually add the dry ingredients to the wet mixture, stirring gently until just combined. Be careful not to overmix.
In another clean bowl, beat the egg whites using an electric mixer or whisk until soft peaks form.
Gently fold the beaten egg whites into the batter in three additions. Use a rubber spatula to fold carefully, maintaining as much volume as possible.
Heat a non-stick skillet over low to medium-low heat and lightly grease it with cooking spray or butter.
Using a ladle, pour about ⅓ cup of batter onto the skillet for each pancake. To achieve extra fluffiness, you can stack additional batter on top.
Cover the skillet with a lid and cook for about 4-5 minutes, until the bottom is golden brown. Flip the pancakes carefully and cook for another 4-5 minutes, covered, until cooked through.
Remove the pancakes from the skillet and repeat with the remaining batter.
Serve immediately with your favorite toppings such as maple syrup, whipped cream, or fresh fruit.