So, I do a lot of cooking from scratch and like experimenting with new ingredients. I was in a real Alladdin's cave of a grocery store today which seemed to stock a properly eclectic mix of middle eastern stuff and east European stuff. I'd love to branch out a bit & thought MN might be place to get ideas about how to use unfamiliar ingredients - particularly spices and flavourings - and how to know whether you're buying good quality stuff.
To get the ball rolling, what is sumac and what is the best way to use it?