Blend the marinade ingredients (onion, garlic, ginger, lemon juice, olive oil, rosemary, thyme, salt, pepper, Ras El Hanout) until smooth, about 20 minutes.

Coat the lamb roast in the marinade. Let it rest and marinate for 1-2 hours, coming up to room temperature before roasting.

Roast at 450°F for 30 minutes, then broil on high for 5 minutes to brown, for medium-rare. For good leftovers, bake until the outer third of the meat reaches 135°F, then rest, covered, for 10 minutes — the middle stays rare, so it reheats well without overcooking.

Alternatively, bake low and slow until fall-apart tender — great shredded for tacos or gyros.