2) Whisk together the stock, soy sauce, sugar, ginger, chili paste, sesame oil, garlic and spring onion whites. Pour over the ribs. Cover and cook on HIGH for six hours.
3) About 30 minutes before serving, put the rice noodles in a bowl with hot water to cover. Soak until tender and pliable, about 30 minutes.
4) Skim any fat that may have collected on top of the beef broth and discard.
5) Divide the noodles among six large shallow bowls and ladle the broth over top. Cut the meat from the ribs if desired and divide the meat evenly among the bowls.
6) Garnish with the carrots, cucumber, coriander, lime and the remaining green parts of the spring onion, plus more chilli paste to taste.