OT needing ice cream experts

DH is a very good sport about our 'fat-free' diet but ice cream used to be
such a favorite of his. So. Therefore. I am going to invent wonderful ice
cream that doesn't contain egg yolks or fat. The stuff at the grocery
leaves an after-taste much like Mop 'n Glo and I'm sure 'we' can do better.
One of the recipes I've found calls for an envelope of powdered whipped
topping. That sounds like it might work. The recipe calls for TWO teaspoons
of vanilla to make only 2½ cups. The ice cream freezer is big enough to
double the recipe but I'm thinking four teaspoons of vanilla is going to be
waaaaay too much. The 'theory' is that your tastebuds are dulled by
something frozen and ice cream needs a heavy hand with flavoring. I'm going
to need some guidance as well as some taste-testers. Naturally, there will
be chocolate cake to go with it. Polly