Simple Noodle Soup

Trim and finely slice the spring onions. Finely slice the lemongrass (if using), peel and finely chop the garlic and deseed and finely slice the chilli. Pick the coriander leaves.
Bring the stock to boil in a large saucepan then reduce to a simmer.
Separate the bok choy leaves (use other greens or frozen peas instead, if you prefer), rinse them and add to the stock together with the prawns, spring onions, lemongrass and garlic.
Cook for a couple of minutes, until the prawns have turned pink and the bok choy has wilted.
Divide the vermicelli between 2 bowls and ladle over the soup.
Scatter the chilli and coriander on top and season with soy and lime juice.