In a frying pan heat the oil and cook the veal rib over moderate heat, turning until browned on all sides. In a flameproof casserole or dutch oven melt the butter and cook the leeks and onions until softened, about 10 minutes, stirring occasionally. Stir the veal, reserved veal bones, bouquet garni, the finely grated zest of one of the oranges, and the tomatoes into the casserole. Season with salt and pepper. Bring to a boil. Reduce heat, cover, and simmer for 1 hour and 20 minutes. Cut the carrots into matchsticks and cook in boiling water for 10 minutes. Drain. About 45 minutes before the meat is done, stir the carrots into the casserole. Five minutes before serving, stir the vermouth and orange juice squeezed from the remaining oranges into the casserole. Serve the meat surrounded by the vegetables.
