Heat the oil in a large saucepan over a medium heat. Fry the beef for 10 minutes, or until lightly browned all over, then set aside.
Tip out any excess oil. Add the stock and scrape up any of the caramelised sticky bits. Add the coconut milk, vinegar, soy sauce, sugar, star anise, garlic, bay leaves and chillies.
Return the beef to pan. Bring to the boil and then simmer, covered, for about 2-3 hours, until the meat is tender. Skim any fat off the surface, if necessary. Season to taste.