1. Preheat the oven to 325°. Wipe the pieces of oxtail with a dampened towel, then sprinkle them with salt and a few grindings of pepper. Dip the pieces in flour and shake them vigorously to remove any excess.
2. In a heavy 12-inch skillet, melt the fat or lard over high heat until it splutters. Add the oxtail (in two batches if necessary) and cook, turning frequently, until the pieces are brown on all sides, regulating the heat so that they color quickly and evenly without burning. With tongs, transfer the meat to a heavy 5- to 6-quarr casserole or Dutch oven.
3. Add the carrot, turnip, celery and onion to the fat remaining in the skillet, and cook over moderate heat, stirring frequently, for 8 to 10 minutes, or until the vegetables are soft and light brown. Spread the vegetables over the oxtail.
4. Then pour in the stock and add the bay leaf, thyme and parsley. Bring to a boil over high heat, cover, and bake in the middle of the oven for 2½ hours, or until the meat can easily be pulled away from the bone with a fork.
5. With a large spoon, skim as much fat from the surface of the cooking juices as you can. Taste for seasoning and serve directly from the casserole.
