Keep it simple: the combination of oxtail and onions has more than enough flavour for this dish.
Apart from the deliciously piquant garnish of some pickled walnuts to this undeniably rich dish, a bowl of steamed floury potatoes simply turned around with a thick slice of butter are, for me, the only other visitors welcome.
Braised oxtail with onions, anchovy, vinegar and parsley (serves 3–4)
1 large jointed oxtail
Salt and pepper
2kg onions, peeled and thinly sliced
2 bay leaves
2tbspn red-wine vinegar
2tbspn anchovy essence
4tbspn chopped parsley
8–10 pickled walnuts
Pre-heat the oven to 140ºC/ 275ºF/gas mark 1. Season the oxtail and then dust with flour all over. Heat the oil and butter in a deep, cast-iron casserole dish that also has a lid. Gently fry the oxtail on all surfaces until crusted and golden. Remove them to a plate, then tip off all but a couple of tablespoons of the fat.
Turn the heat down to almost nothing, lay half of the onions in the bottom of the pot, reintroduce the oxtail in one layer together with the bay leaves and then cover with the rest of the onions.
Lay a buttered sheet of greaseproof paper (butter side down) upon the surface and put on the lid. Leave on the low heat for a couple of minutes, then slide the pot into the oven and cook for 2–3 hours—or until very tender and the meat is clearly seen to be falling away from the bone when nudged.
Remove from the oven and carefully lift out the pieces of oxtail with a slotted spoon onto a plate. Place the pot back onto a moderate heat and stir together the onions, which should now have collapsed to a golden goo. Stir in the anchovy essence, vinegar and parsley and return the oxtail, burying it in the onions.
Set the pot (without lid) over a moderate flame and simmer for a further 15–20 minutes, until the onions are sticky and unctuous. Serve directly from the pot onto hot plates, while also handing around the slices of pickled walnuts at table.