Preheat oven to 325°.
Combine first 8 ingredients.
Heat a large nonstick skillet coated with cooking spray over medium-high heat. Add lamb; cook 8 minutes on all sides or until browned. Remove lamb from pan. Add onion to pan; cook 5 minutes or until tender, stirring frequently. Stir in half of chile mixture and tomato purée; cook 3 minutes, stirring occasionally. Stir in lamb and water; bring to a boil. Reduce heat; simmer 5 minutes.
Wrap handle of skillet with foil, and bake, covered, at 325° for 1 hour. Stir in bell pepper, squash, carrot, saffron, and cinnamon. Cover and bake an additional 40 minutes. Stir in remaining chile mixture and apricots. Cover and bake an additional 15 minutes. Remove cinnamon stick; serve over couscous. Sprinkle with cilantro.
Adding the spice paste in two stages gives depth and brightens the flavor. Leaving the cinnamon whole keeps its influence subtle. Moroccan tagines tend to be warmly and sweetly spiced rather than hot.