1. Place the noodles in a large heatproof bowl, pour over boiling water to cover and leave to stand for 5 minutes.
2. Meanwhile, in a medium saucepan, place the stock, Very Lazy Lemongrass paste, Very Lazy chopped ginger and chillies and spring onions. Bring to the boil and simmer for 5 minutes to allow the flavours to infuse.
3. Sir in the pak choi, prawns and beansprouts and simmer for 3 minutes. Stir in the coriander.
4. Drain the noodles and divide between 2 large deep bowls, ladle over the soup.