Cut ox tail at joints, parboil five minutes, wash thoroughly, dredge with flour, and sauté in butter (to which has been added a sliced onion) until well browned. Add one-fourth cup flour, two cups each brown stock, water, and canned tomatoes, one teaspoon salt, and one-fourth teaspoon pepper. Turn into an earthen pudding-dish, cover, and cook slowly three and one-half hours. Remove ox tail, strain sauce, and return ox tail and sauce to oven to finish cooking. Add two-thirds cup each carrot and turnip (shaped with a vegetable cutter in pieces one-inch long, and about as large around as macaroni) parboiled in boiled salted water five minutes. As soon as vegetables are soft, add Sherry wine to taste, and more salt and pepper, if needed. The wine may be omitted.