1.Heat a large saucepan over medium-high heat. Stir in the lamb, breaking it up into crumbles, and cook until browned (with no visible pink). Set lamb aside.
2.In the same pan, saute celery, onion, allspice, salt, cayenne, bay leaves, oregano, and garlic, until softened. Add in the tomatoes and their juice, water, and orzo. Bring the mix to a boil.
3.Reduce the heat to medium low, cover, and simmer, stirring occasionally, until the orzo is tender and has absorbed the liquid, about 15 minutes. Combine orzo with the cooked lamb and sprinkle with feta cheese and mint leaves.