Preheat oven to 350 F.
Separate the egg yolks and whites.
Beat whites until peaks form.
In a separate bowl, mix yolks, greek yogurt, and baking soda.
If adding a sweetener and/or flavor variation, do this now into the yolk mixture.
Gently fold the egg yolk mixture into the egg whites.
Transfer batter into an 8" lined or oiled pan.
Bake for 30 min.
Turn off the oven, open the door slightly and let it cool in the oven for 15-20 min.
Refrigerate a few hours before slicing and topping (if desired)
