Salt and pepper lamb. Cut slits in roast and insert slivers of garlic. In a heavy roasting pan with cover, sear lamb on all sides in hot oil. Add carrots, onion, and green pepper; brown. Stir in tomatoes, thyme, and oregano. Cover and braise at 325 degrees for 1–1/2 hours or until desired degree of doneness: 145 degrees for medium-rare, 160 degrees for medium or 170 degrees for well. Remove roast and vegetables. Skim off excess fat and boil pan juices for about 3–5 minutes to reduce. Stir in cilantro and lemon juice. Adjust salt and pepper to taste. Serve lamb roast sliced with meat juices and salsa.