Extra virgin olive oil, sf.
Dan, you might be amazed at the number of people who have shocked reactions when I tell them I use EVOO in brownies/cake/etc. Even when I tell them it somehow makes the chocolate richer, kind of more chocolaty, they get this "yeah, sure" look and say "I'll just have to trust you on that" - but clearly they don't. But hey - if they want to miss out, that's their choice!