Rinse the meat under cold running water to remove any blood and impurities. Place the meat in a pot and drizzle with salt. Add the water and bring to the boil. Skim off and add more water if necessary. You should end up with about 1.5 litres of stock. Brown the onions in a pan and add the onions and ginger to the stock. Roast the spices in a dry oven dish to bring out the flavours. Add to the stock and simmer for 3–5 hours or until the meat is tender. Drain the stock through a sieve and add the fish sauce and brown sugar to taste. Cut the meat into small pieces and place in a bowl. Add the stock, bean sprouts, spring onions, slices of sirloin, rice noodles and herbs. Top with the herbs and add the lime juice, hoisin sauce and sriracha sauce to taste.