Preheat griddle to 325º. (This is a thick batter and needs to cook at a slightly lower heat, because they brown up quickly.)

In a large bowl, whisk together the flour and cornstarch until well combine; whisk in baking powder and ¼ teaspoon of salt. Set aside.

In a large bowl, beat the egg whites until frothy. Add the remaining ¼ teaspoon salt and continue beating until soft peaks form.

In blender jar add the ricotta, milk, egg yolks, sugar, lemon zest and juice and pulse until smooth. Add to flour mixture and mix until just combined.

Using a rubber spatula, gently fold the beaten egg whites into the pancake batter.

Spray the griddle with nonstick cooking spray. Ladle ⅓ cup batter onto the griddle for each pancake. Cook until bubbles form on top and the pancakes are golden underneath, 1 to 2 minutes. Flip the pancakes and cook for 1 minute more. Repeat with the remaining batter.