This recipe was a great starting point for me. Thanks so much for posting it. I made a few changes to it that I thought I would post in case anyone else out there doesn't like tomato :)
I used the egg whites that you buy in the store from Lucerne (that's the brand) its 4 cups even because I like to double the recipe.
I took out shrimp and tomato and added mushroom. I cooked the recipe the exact same way otherwise. I used a stone from pampered chef, although I think you can get stones pretty much anywhere now.
With the clarified butter, I basted the stone with a brush for the butter.
I am going to cut it into squares like brownies because I used a rectangle baking pan. Then I can freeze some for later.