Pour the stock into a large saucepan and bring to a boil.
Add in the ginger, chilli, spring onions, Chinese five-spice powder, sugar, sweet chilli sauce and soy sauce, and reduce to a simmer for 5 minutes.
Next, add mushrooms and noodles. Simmer for another three to four minutes until the noodles are cooked. Stir in the bok choy and lime juice, and season with salt and pepper. Allow to cook for two more minutes, then ladle into bowls and serve.