1 litre (1 3/4 pints) light and clear chicken or vegetable stock
3 tablespoons Thai fish sauce
1 tablespoon rice wine vinegar
1 tablespoon lime juice
1 tablespoon palm sugar or soft light brown sugar
1 garlic clove, sliced
1 red chilli, sliced thinly
3 kaffir lime leaves
2 teaspoons tamarind paste
200 g (7 oz) rice vermicelli
125 g (4 oz) baby corn, sliced
250 g (8 oz) raw peeled tiger prawns
100 g (3 1/2 oz) bean sprouts
2 tablespoons shredded mint
Pour the stock into a large saucepan and add the fish sauce, vinegar, lime juice, sugar, garlic, chilli, lime leaves and tamarind paste. Bring to the boil over a medium-high heat, then reduce the heat and simmer gently for 12 minutes.
Meanwhile, put the rice vermicelli in a bowl of boiling water for 2–3 minutes until tender, or cook according to the packet instructions. Drain well and divide among warmed deep serving bowls.
Stir the baby corn into the broth and simmer for 2 minutes, then add the prawns and simmer for a further 2–3 minutes until the prawns are just cooked.
Ladle the broth into the bowls of vermicelli, then scatter over the bean sprouts and mint and serve immediately.