In a large mixing bowl, whisk together the flour, granulated sugar, baking powder, and salt until well combined.

In another bowl, mix the milk, egg yolks, vanilla extract, and melted butter until smooth.

Gradually add the wet ingredients to the dry ingredients, stirring until just combined. Do not overmix; a few lumps are okay.

In a separate bowl, beat the egg whites with an electric mixer until stiff peaks form.

Gently fold the egg whites into the pancake batter in three additions, being careful not to deflate the mixture.

Preheat a non-stick skillet or griddle over low heat and lightly grease with butter.

Using a ring mold or a 1/4 cup measuring cup, pour the batter onto the skillet. Cook for about 4-5 minutes until bubbles form on the surface.

Carefully flip the pancakes and cook for an additional 4-5 minutes until golden brown and fluffy.

Remove from the skillet and serve immediately, dusted with powdered sugar and topped with maple syrup and fresh berries if desired.