Step 2

Carefully strain the hot broth into a large heatproof bowl or jug, discarding the prawn heads. Return the strained vegetable and herb mixture to the saucepan and pour over the broth. Stir through the mushrooms and lime leaves, then cook for 3 minutes until the mushrooms are tender.

Step 3

Add the sugar, fish sauce, lime juice, coconut milk and prawns. Bring to the boil and cook until the prawns are cooked through, about 1–2 minutes. Remove from the heat, remove the lemongrass, then stir in the Thai chilli jam if using. Scatter over the coriander and serve.