Lamb Tagine with Artichokes, Lemon and Olives (morocco)

For 4 - 6 people.. Trim excess fat from the lamb. In a large casserole toss the lamb chunks with the garlic, salt, spices, oil, herbs and onion. Cover with 225 ml (scant 1/2 pint) water and bring to the boil. Reduce the heat, cover, and simmer over moderate heat for 1 1/2 hours, turning the pieces of meat often in the sauce and adding water whenever necessary. Prepare the artichokes by removing the outside leaves and trimming the bases. Halve each one and remove the hairy choke. Place in acidulated water (water with 2 tablespoons of vinegar added) to keep from blackening while trimming the rest. Rinse and drain before using. Place the artichokes over the pieces of meat after the meat has cooked 1 hours. Place the rinsed preserved lemons, cut in quarters, on top. Cover tightly and cook 30 minutes. Sprinkle with lemon juice olives and cook a few minutes all together. Place the lamb in centre of the serving dish. Arrange the artichokes, flat side up, facing in one direction around the rim. By boiling rapidly, uncovered, reduce the sauce to a thick gravy. Adjust the seasoning of the sauce. Swirl the pan once to combine and pour over the meat. Decorate with preserved lemons and olives and serve at once. Note : An alternative sauce includes a peeled and seeded tomato cooked with the sauce.