Preheat the oven to 190C/375F/Gas 5. Trim most of the excess fat from the beef shin, leaving on some for colour and flavour. Prepare the beef by taking the meat off the bone in seams and cut into big chunks. Season well with sea salt and freshly ground black pepper. Heat a little oil in a frying pan and fry the pieces of beef until browned on all sides.
Heat a little more oil in a heavy-based flameproof casserole. Add the vegetables and star anise and cook briefly until the vegetables are just soft. Pour in the red wine and port and bubble until the liquid has reduced by half. Add the beef and pig's trotter and cover with the stock. Bring to the boil, skimming off any scum that rises to the surface, then add the stout, soy sauce and fish sauce. Transfer to the oven and cook for three hours, or until the meat is very tender.
Take the casserole out of the oven, remove the meat from the pan and keep warm. Strain the cooking liquid, return it to the pan and bring to the boil. Let it bubble until the sauce is thick then season with sea salt and freshly ground black pepper. Take the pig's trotter out of the meat mixture and reserve the meat – it is delicious on toast. Return the beef to the pan and put it back in the oven for a further 30 minutes.
Meanwhile, make the parsnip purée. Place the parsnips and shallots into a saucepan with the milk, cream and bay leaves and cover with water. Add the olive oil and lemon juice and a good pinch of salt and bring to the boil. Reduce the heat and simmer gently for 15-20 minutes. Drain the vegetables, reserving the cooking liquid, and discard the bay leaves. Place the vegetables in a food processor and blend with enough cooking liquid to make a purée with the consistency of whipped cream. Season with salt and freshly ground white pepper and keep warm.
Spoon the meat onto warmed plates and serve with the parsnip purée.