First prepare the marinade. Mix together the chiles (use only one of each if you don’t like hot dishes), smoked paprika, oregano, cumin seeds, cinnamon sticks, garlic, 1 tablespoon of olive oil, and salt and pepper to taste. Rub the mixture into the lamb so that it is well flavored. You can cook the lamb right away, but if you have time, cover and leave to marinate for at least 1 hour, or even overnight.