Make ahead: 2 days
Wrap the first four ingredients in a square of cheesecloth or put in a tea infusion ball, and place in a large saucepan.
Add the beef broth, rice vinegar and the meat. Season with salt and pepper and bring to a boil. Reduce heat to low and simmer 3 hours, skim as needed.
Remove the wrapped herbs and discard. Remove the meat and wait 15 minutes before cutting into thin strips, perpendicular to the direction of the meat fibre.
Bring broth to a boil and turn off the heat. Return the meat to the broth and add the two types of onions.
Cover and serve immediately in a soup tureen.
Serve with Haiku rice vernicelli (prepared according to instructions on the package and lightly toasted in sesame oil), bean sprouts, Haiku minced coriander and various sauces (hoisin, fish and chilli).