Ingredients
1 litre/2 pints chicken stock
300ml/11fl oz water
6 sticks lemongrass, lightly crushed
4 fresh coriander roots, crushed
110g/4oz fresh galangal, peeled and sliced (available from Asian supermarkets)
8 tomatoes, cut into quarters, seeds removed
6 kaffir lime leaves
1-2 limes, juice only
75ml/3fl oz tamarind water (Soak the tamarind in hot water and push the pulp through a sieve to make tamarind water.)
3 red chillies, thinly sliced
75ml/3fl oz fish sauce (nam pla), or to taste
75g/3oz palm sugar (available from Asian supermarkets), use brown sugar if unavailable
12 raw tiger prawns, shelled, gutted and split in half
2 boneless skinless chicken breasts, cut into chunks
1 small bunch fresh coriander, leaves
1 small bunch fresh Thai basil, leaves (available from Asian supermarkets)
lime wedges
Method
Place the stock and water into a large pan over a high heat and bring to the boil.
Add the lemongrass, coriander roots, galangal, tomatoes, lime leaves, lime juice, tamarind water and red chillies. Return to the boil, then reduce the heat and simmer for 15-20 minutes.
Taste the stock and add as much fish sauce and palm sugar as necessary to keep the salty-sour-hot-sweet taste, then remove from the heat.
Transfer 220ml/8fl oz of the stock into a separate pan over a high heat and bring to the boil. Add the chicken and cook for 1-2 minutes, then add the prawns and cook for a further 1-2 minutes, or until completely cooked through.
To serve, pour the soup into two bowls and top up with the hot stock. Garnish with Thai basil, coriander and a wedge of lime.