Heat 2 tablespoons of oil in a large shallow frying pan over a medium-low heat and gently cook the shallots and garlic until fragrant but not coloured. Transfer to a large ovenproof dish and set aside.
Pack the oxtail over the shallots and garlic, then add the cloves, fresh ginger and a good grating of nutmeg. Add the peel from the fresh orange or use dried orange peel, then cover with 2cm to 3cm of water.
Place in the oven for 15 minutes, then reduce the temperature to 140ºC/gas 1. Gently simmer for around 2 hours 30 minutes (depending on how big the bones are), or until the meat is just tender. Check the liquid level from time to time, adding more water if necessary.