Slice the onion finely and add to a large pot with the garlic and ginger.
Chop the leek.
Add the stock cube to the 950ml of water. Pour in the snap peas and add chilli flakes. Add more water if desired. Let simmer for 5 minutes.
Add the noodles, cinnamon and star anise and stir infrequently until noodles are tender but firm.