Preheat the waffle iron.
Preheat oven to 200°F. This step is optional, but it helps to maintain waffle disks crispy until all the batter is cooked.
Separate the egg yolk from the egg white. In a medium bowl whisk egg yolk, butter, milk and vanilla extract until well combined.
In a medium bowl, whip egg white to stiff peaks.
In a large bowl, stir together all-purpose flour, cornstarch, baking powder, sugar and salt until well mixed.
Add the liquid mixture, and whisk only until everything looks homogeneous. Careful to not overmix.
Gently fold the whipped egg white.
Pour batter into preheated waffle iron and cook until ready. It usually takes from 3 to 4 minutes, depending on how much golden brown you want your waffles.
Place waffles disks directly into the oven rack as soon as they’re cooked, to keep them warm and crispy while finishing the remaining batter.
Serve warm, with topping of your choice.