I’m leaning toward apple sauce. It’s already something that’s eaten on its own. In terms of a savory sauce, if dressings count—I think they do—then greek dressing would be my answer. Dressings in general tend to be more drinkable than typical condiments. Anyways, what’s your opinion?
Then I’m interested in seeing what happens if you thin out the sauce that makes duck a l’Orange and ferment it.