If you have ever travelled in the East, or even just been to a Thai restaurant, you will find the flavours of this soup evocative. If you live near an oriental grocer’s, buy a jar of Thai sour shrimp paste (sometimes called tom yum,) —
Put the tomatoes into a bowl, pour over boiling water to cover and leave for 2 minutes, then peel and cut into small cubes. Peel the ginger and garlic and slice across very thinly. Cut the chillies open under running water, discard the seeds and stem and slice the chillies across very finely. Pour the stock into a large, heavy-based saucepan and add the lemon juice, tomatoes, ginger, garlic and chillies. Bring to the boil (adding the shrimp paste now, if used), then cover the pan and simmer gently for about 20 minutes.
Meanwhile, slice the mushrooms finely across. Slice the cod fillet across at 1.25cm/½ in intervals. Trim the spring onions and cut them across fairly thinly, using as much of the green part as possible. Roughly chop the coriander leaves.
Put the coconut milk powder into a measuring jug, pour in the boiling water and stir until smooth. Stir this into the stock and tomato mixture and bring to the boil. Then add the sliced mushrooms, cover and simmer for another 15 minutes.
Shortly before serving, drop in the slices of cod, bring up to bubbling again, then remove from the heat immediately. Add the spring onions, then leave the pan covered on top of the stove for 5-8 minutes, until the fish is lightly cooked through. Taste the liquid and add salt if necessary, then pour into a heated soup tureen and very roughly stir in the chopped coriander leaves.
© 1997 Josceline Dimbleby. All rights reserved.