Start by whisking the egg whites into soft peaks, just keep on whisking until they are solid.
Then in another bowl, mix together the yolks salt, and sugar until well blended. Then mix in the melted butter, flour, baking powder, ricotta cheese, and lemon zest.
Once that batter is well combined, mix in the egg whites.
Spray an air fryer safe pan with non-stick cooking spray, and then pour the batter into the pan.
Bake at 320 degrees F, for 20 minutes. Check your cake, see if it is done, if not add an additional 5 minutes.