5 sticks lemongrass, lightly crushed
8 fresh coriander roots, crushed
220g fresh galangal, peeled and sliced (available from Asian supermarkets)
12 pomodorino tomatoes, cut into quarters, seeds removed
10 kaffir lime leaves
3 to 4 limes, juice only
3 tablespoons of tamarind paste
150ml fish sauce (nam pla), or to taste
150g palm sugar (or brown sugar if unavailable)
3 raw tiger prawns per serving, shelled, gutted and split in half
fresh coriander leaves
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.
Add the prawns and cook for a further 1-2 minutes, or until prawns are completely cooked through.
Add the coconut milk and turn off the heat.