Preheat the oven to 150°C.
Wash oxtail pieces, pat dry, and trim excess fat.
Toss meat in seasoned flour until well coated.
Brown oxtail in oil for 10 minutes in a non-stick frying pan.
Transfer browned meat to a flameproof casserole dish.
Sauté onions, garlic, carrots, and celery in the pan for 10 minutes.
Add vegetables, herbs, wine, stock, and tomato purée to the casserole.
Bring to a simmer on the hob then cover with a lid.
Cook in the oven for 3 hours, stirring once halfway through.
Remove oxtail from sauce and skim fat from the surface.
Serve meat topped with sauce and fresh parsley.