In a large saucepan, place the chicken stock, ginger, spring onions and soy sauce. Turn the heat on and bring to a simmer. In the meantime, bring a large pot of water to the boil. When the broth starts to simmer, place a ladle of the warm broth in a large bowl. Add the miso paste and whisk until smooth. Then transfer the miso mixture back into the simmering broth. Turn the heat off. Cook the noodles in the large pot of water until just al dente. Use tongs to transfer the noodles into serving bowls. Keep the water boiling. Now add the dumplings to the water and cook for 4-5 minutes or until cooked through. Transfer the dumplings to the serving bowls. Keep the water boiling. Use scissors to slice the choy sum into the boiling water and blanche for about 30 seconds. Transfer the choy sum to the serving bowls too. Ladle the broth into the serving bowls. Top with boiled eggs and drizzle with chilli oil, if using.