1. Heat chicken stock in a large pot. Add star anise, ginger, coriander stalks, chilli, fish sauce, choy sum and soy sauce.
  2. Bring the stock to the boil and then add the pasta.
  3. Boil for 6 minutes
  4. Once pasta is cooked, turn the heat off. Add the lime juice.
  5. Divide the soup and pasta amongst 4 bowls.
  6. Garnish each bowl with coriander leaves