I like the fact that it uses coconut flour instead of almond flour. I'm going to have to bake this soon!
I'm not an expert on baking but I've seen recipes that call for cream of tartar to stablize egg whites. I wonder if it would work with whipped cream? You could alway try the coconut milk whipped cream. You just put a can of coconut milk in the frig overnight and use the cream off the top. I've made that and mixed a little vanilla extract and stevia and it's good.