This is the famous Tom Yum Goong which anyone who knows and appreciates Thai food has experienced.
1 kg/2 lb medium or small raw prawns
1 tablespoon oil
2 litres/4 pints/8 cups prawn stock
salt to taste
2 stalks lemon grass, bruised
or 4 strips thinly peeled lemon rind
4 kaffir lime leaves
4 fresh red chillies
2 tablespoons fish sauce
lime or lemon juice to taste
2 tablespoons chopped coriander leaves
4 spring onions (scallions), including green tops, chopped
Shell and devein prawns, reserving heads and shells. Heat oil in a saucepan and fry heads and shells until they turn pink. Add 2 litres (4 pints) hot water, salt, lemon grass or rind, kaffir lime leaves and 3 of the chillies left whole. Bring to the boil, cover and simmer for 20 minutes. Strain stock, return to pan and bring to the boil. Add prawns and simmer for 3 minutes, or just until prawns are cooked. Stir in fish sauce and lime or lemon juice to taste, making it nicely piquant. Serve sprinkled with remaining chilli finely chopped, coriander leaves and spring onions.
Recipe excerpted from Encyclopedia of Asian Food by Charmaine Solomon (Periplus Editions, 1998)