Position rack in lowest third of oven and preheat to 325 degrees. Heat oil in heavy large pot or Dutch oven over high heat. Add all lamb bones and cook until brown, turning often, about 15 minutes. Transfer bones to plate.

Season lamb with salt and pepper and dredge thoroughly in flour. Add to pot and cook until brown on all sides, about 10 minutes. Transfer lamb to plate with bones.

Add onions and garlic to pot and cook until onions are just golden, scraping up browned bits, about 5 minutes. Return lamb to pot. Arrange bones around lamb. Stir in stock and next 7 ingredients. Bring liquid to boil. Baste top of lamb. Cover; bake until lamb is tender when pierced with long sharp knife, turning once, about 2 hours 15 minutes. Cool; cover and chill overnight.

Preheat oven to 325 degrees. Remove fat from surface of lamb and cooking liquid. Transfer lamb to platter. Remove string from lamb. Cut into 1/2-inch-thick slices. Arrange in shallow baking dish.

Bring pan juices to boil. Remove bones and discard. Strain pan juices, pressing hard on solids to extract as much liquid as possible.

Melt margarine in same pot over medium heat. Add 1 1/2 tablespoons flour and stir until mixture begins to brown, about 2 minutes. Whisk in pan juices and boil until sauce is reduced to 2 cups, about 15 minutes. Season with salt and pepper.

Pour over lamb. Cover with foil and bake until lamb is heated through, about 25 minutes. Arrange lamb on platter. Spoon sauce over. Garnish with parsley.

This recipe yields 8 servings.

Comments: Order the lamb from your butcher, and buy the pomegranate juice at a Middle Eastern market or at a natural foods store. Begin preparing this richly flavored main course one day ahead.