15g tamarind paste
16 large raw prawns with shell
500ml chicken stock
1-2 medium hot red chillies, roughly chopped
30g fresh ginger, roughly chopped
3 fat cloves garlic, roughly chopped
1 bunch coriander with roots* washed and roughly chopped
50ml sesame oil
1 teaspoon ground coriander seed
250g ripe tomatoes, peeled and chopped
400ml coconut milk
1 red pepper, finely sliced
Asian fish sauce, to taste
200g dried rice vermicelli noodles, cooked according to the packet instructions
A handful of fresh mint leaves
4 spring onions, finely sliced
1 lime, quartered

* Oriental shops usually sell coriander with its roots, but don't worry if you can't find it like that; it just gives a deeper coriander flavour to the dish.

Instructions
Place the tamarind paste in a small bowl. Cover with 150ml hot water and roughly break up with a fork. Leave to soak while you prepare the prawns.

Wash and peel the prawns, saving their shells as you do so. Put the shells in a saucepan with the stock and simmer for 20 minutes, then strain and discard the shells.

Meanwhile, clean the prawns by running a knife down the length of their backs and removing their thin black digestive thread. Rinse once again, pat dry and chill, covered, until needed. Using your hands, rub the tamarind paste to loosen as much of the pulp as possible from the stones. Strain into the stock.

Put the chillies, ginger, garlic and fresh coriander in a food processor with the sesame oil. Purée until it forms a paste, then transfer to a saucepan. Add the ground coriander seeds and set over a medium heat. Stir-fry until it begins to release a delicious aroma, then add the tomatoes and cook until they form a thick paste. Mix in the stock and coconut milk. Bring up to the boil and simmer for 5 minutes.

Add the prawns and sliced pepper and simmer for 2 minutes or until the prawns are pink and just cooked. Season to taste with about 1 teaspoon fish sauce. Divide the rice noodles between 4 large bowls and ladle in the spicy prawn soup. Top with fresh mint leaves and sliced spring onions and serve with lime wedges.