Soak the oxtail pieces in cold water for 1 hour (at least). This will draw out some of the blood. Drain the oxtail, then dry and trim off as much external fat as you can. Season the flour by generously salting and peppering a plateful.
Heat a casserole with a little oil over a medium heat, then add the pancetta, half the celery, the carrot and the onion. Sweat for 10–15 minutes, taking care not to burn, and then add the garlic, chilli and bay leaves.
While this process is going on, with only the occasional prod or stir from you, heat a little oil in a large frying pan. Dredge the oxtail pieces in the seasoned flour then brown lightly and thoroughly over a medium flame on all sides. On no account burn the flour crust, it will spoil the taste of the whole dish. As and when the oxtail is browned, transfer to the casserole, then deglaze the frying pan by pouring in the red wine and boiling rapidly. Tip this into the casserole, then add the tomatoes and enough water to barely cover the meat. Stir thoroughly to ensure an even distribution of the chilli. Bring the casserole back to a simmer, turn the heat down to very low, then cover and simmer for 2 hours. Turn the meat once after an hour. When the 2 hours are up, allow to cool in the casserole and refrigerate overnight when completely cold.
The next day, or 1 hour before serving, scrape off any fat from the surface of the casserole. Bring the casserole back to a simmer (be careful that it does not scorch on the bottom). When simmering, add the remaining celery, then season cautiously and simmer very gently for an hour. About 5 minutes before serving add the cocoa. Stir in and check the seasoning. Turn the heat off and allow the meat to cool slightly before serving. It’s great with chopped parsley mash (or rocket mash or garlic mash).
© 1996 Alastair Little. All rights reserved.