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

In another bowl, beat the egg yolks and add the milk and vanilla extract. Mix until smooth. Gradually add the dry ingredients to the wet mixture, stirring until just combined.

In a separate bowl, beat the egg whites until soft peaks form. Gradually add 1 tablespoon of sugar and continue to beat until stiff peaks form.

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

Heat a non-stick skillet over low heat and add a small amount of butter. Pour about 1/4 cup of batter into the skillet. Cover with a lid and cook for about 4-5 minutes, or until bubbles form on the surface.

Carefully flip the pancake and cook for another 4-5 minutes, covered, until golden brown and fluffy. Repeat with the remaining batter, adding more butter as needed.

Serve warm, dusted with powdered sugar and drizzled with maple syrup or topped with fresh fruit.