Whisk flour, baking powder, and salt in a large bowl.
Combine milk, egg yolks, vanilla or almond extract and melted butter in a large liquid measuring cup or bowl.
Combine the wet ingredients with the dry ingredients and mix to combine. Careful not to over mix - lumps are okay.
Whip egg whites into soft peaks. Gradually add sugar and whip until stiff, but not dry.
Carefully fold egg whites into batter - streaks of egg whites are okay.
Heat a non-stick griddle or skillet over medium heat. Brush with melted butter. For each pancake, fill a 1/4 cup measure with batter and drop onto griddle. They are ready to flip when the bottoms are brown and large bubbles appear on the surface. Repeat with remaining batter, brushing the griddle with more melted butter as you go.
Serve warm with lots of butter and warm maple syrup.
** This recipe is kind to multiplying if you'd like to make a double or triple batch for a bigger crowd. You can also try mixing in bananas, blueberries, chocolate chips, walnuts [or anything really] to to the batter.