Tom Yam Soup
rec.food.recipes/Jane Sales (1994)

1 tablespoon vegetable oil
1 lb fresh prawns, shelled but with heads reserved
2 pints fish stock or water
1 stalk lemon grass cut into 1 inch lengths
4 fresh green chillis, thinly sliced
salt to taste
2 teaspoons fish sauce (Nam Pla) or light soy sauce
2 tablespoons tamarind water or fresh lemon or lime juice

Garnish
Finely chopped coriander leaves
1 red chilli, seeded & thinly sliced

Heat the oil in a saucepan and add the prawn heads. Stir fry for 3-4 minutes, and then add the stock, lemon grass, chilli and salt to taste.

Bring to the boil, reduce the heat, cover and simmer for 15 minutes.

Strain the mixture through a fine sieve and return the stock to the pan. Bring to the boil and add the prawns, then reduce the heat and cook until the prawns are tender but still firm. (About 3 minutes.)

Remove from the heat, stir in the fish sauce and lemon juice. Put the soup into a tureen, sprinkle with the fresh coriander and chilli and serve at once.