Remove the fell (tissue-like covering) from lamb with a sharp knife. Rub surface of lamb with Italian seasoning, salt, and pepper; brown lamb in butter on all sides in a large stock pot. Remove lamb; set aside. Reserve pan drippings in stock pot. Add carrots, onion, and garlic to pan drippings. Cook over medium heat until onion is tender.
Place browned lamb in stock pot over vegetables. Combine beef broth and wine; pour over lamb. Cover and simmer 3 hours or until lamb is tender, basting occasionally.
Transfer lamb and vegetables to a warm serving platter, reserving pan drippings.
Skim fat from pan drippings; discard fat. Combine 2 tablespoons flour and cold water; stir until smooth. Combine flour mixture and pan drippings; cook, stirring constantly, until mixture is thickened and bubbly. Serve gravy with lamb and vegetables.