1. Preheat the oven to 160°C.
2. Add oil to a deep frying pan big enough to fit the beef shin and place on a medium-low heat.
3. Season the shin with salt then add to the pan. Colour on all sides until golden brown,about 5-7 minutes. Remove from the pan and reserve.
4. Add onion,star anise and cinnamon to the pan. Sweat for about 5 minutes,then add garlic and cook for a few more minutes.
5. Add Shaoxing wine,scraping the bottom of the pan,then add both soy sauces,black vinegar,sugar and chilli bean paste. Bring to the boil,then simmer for 2 minutes. Add stock,bring to a simmer,then check seasoning.
6. Transfer the beef shin into a casserole dish or heavy-bottomed oven tray. Carefully add sauce - it should cover half to three-quarters up the shin (add a little boiling water if needed),then cover tightly with foil or a lid. Cook in the oven for6 hours,until the beef falls off the bone easily.
6. Remove from the oven,allow to sit for 20 minutes. Carefully transfer the shin and sauce to a deep serving platter. Garnish with coriander and crispy-fried onions and serve.
*You'll find Shaoxing wine and Chinkiang vinegar at Asian supermarkets - the Chinkiang is more savoury and fragrant than balsamic vinegar,and makes a great dipping sauce.