Prawn Laksa

20-24 large raw unpeeled prawns
450ml / 16 fl oz fish stock
pinch of salt
1 tsp peanut oil
450ml / 16 fl oz coconut milk
2 tsp nam pia (Thai fish sauce)
1/2 tablespoon lime juice
115g / 4 oz dried medium rice-flour noodles
115g / 4 oz bean sprouts
fresh coriander, chopped, to garnish

To the Laksa paste
6 fresh coriander stalks with leaves
3 large garlic cloves, crushed
1 fresh red chilli, deseeded and chopped
1 lemon grass stalk, centre part only, chopped 2.5cm / 1in
piece fresh ginger, peeled and chopped
1 1/2 tbsp shrimp paste
1 1/2 tsp ground turmeric
2 tbsp peanut oil

Remove the heads and shells from the prawns, leaving the tails intact, and devein. Reserve the heads and shells. Put the fish stock, salt and the prawn heads and shells in a saucepan over a high heat and slowly bring to the boil. Lower the heat and simmer for 10 minutes.

Meanwhile, make the laksa paste, Put all the ingredients, except the oil, in a food processor and blend. With the motor running, slowly add up to 2 tablespoons of peanut oil just until a paste forms, (If your food processor is too large to work efficiently with this small quantity, use a mortar and pestle.)

Heat the 1 teaspoon of peanut oil in a large saucepan over a high heat. Add the paste and stir-fry until it is fragrant. Strain the fish stock through a sieve lined with muslin. Stir the stock into the laksa paste, along with the coconut milk, nam pia and lime juice. Bring to the boil, then cover and simmer for 30 minutes.

Meanwhile, soak the noodles in a large bowl with enough lukewarm water to cover for 20 minutes, until soft. Drain and set aside.

Add the prawns and bean sprouts to the soup and continue simmering just until the prawns turn opaque and curl. Divide the noodles between 4 bowls and ladle the soup over. Serve garnished with chopped coriander.