Combine stock and coconut milk in a large saucepan, add sugar and salt and bring to the boil. Place coriander roots, lemongrass, turmeric, garlic and chilli flakes in a food processor and whiz until finely chopped or crush in a mortar and pestle. Add mixture to hot stock and simmer for 5 minutes. Add prawns and simmer until prawns just change colour. Add coconut cream, fish sauce and lime juice and stir.
Ladle soup into warm bowls and top with coriander leaves.
- Main Ingredients - Shellfish