cooking.nytimes.com
Start with lamb shoulder; leg is not lean or tender enough for this treatment. You can use loin if you prefer, but the dish will cost at least 10 times as much and it won’t be any better. Marinate it dry (or nearly so; I use a little soy sauce, for complexity) for as long as you like — 10 minutes, an hour, a day. The flavor will get a little stronger, though not much. More important than the length of time is the freshness of your cumin. You absolutely need cumin seeds, not ground cumin. It’s worth the two or three minutes it takes to toast the seeds before marinating the meat. You can grind them if you like, but I like the little bit of crunch the seeds add.