Heat the oil in a large pan over a high heat. Briefly stir-fry the garlic, ginger, chilli and spring onion whites, then add the peppers, carrots, celery, coconut milk and stock. Stir in the tomato purée and add the chicken, cover and bring to the boil.
Simmer for 6-8 minutes, until the veg is wilted and the chicken heated through. Season with the lime juice, fish sauce and coriander.
Add the sugar snap peas and the spring onion greens. Simmer for 5 minutes. Ladle into bowls and drizzle with chilli oil. Serve lime wedges on the side, if you like.
This recipe is taken from Delicious Soups by Belinda Williams (Ryland Peters & Small, £16.99)