Food & Drink: Salting away the treasures of the sea: It is prized in Portugal, beloved of the Basques and the traditional standby for Catholic fast-days, but salt cod is no longer a Mediterranean preserve

Salt cod has never made much of a mark in this country. It needs Catholicism and/or heat to boost it to a high-ranking position in the food order. In the past, the strict dictates of the Catholic faith brought a demand for a regular supply of fish on weekly fast-days - not only Fridays, but often several other days. It was all very well to rely on fresh fish if you lived on the coast, or had access to a teeming river. But what if you did not?

And what if the temperature in summer soared to a fish-rotting height by mid-morning? No refrigeration, bad roads, snail-slow transport . . . The possibility of laying your hands on edible fish would have been minimal. Salt cod, dry as a bone, flat and relatively lightweight, was the answer. As long as it was stored away from damp, it would keep and keep.

Salt cod was a comparatively cheap form of protein in the past. Now it has become a luxury item in those Mediterranean countries where it was once a fast-day necessity. Nowhere more so than in Portugal, where they claim to have a different way of cooking it for every day of the year. There is a marvellously whiffy street in Lisbon where virtually every other shop specialises in salted fish and other dried foods. Enter any one of them, and you will see an astonishing array of salt cod, graded according to provenance and quality. The best of it will swell to a thickness of 2-3in (5-7.5cm) when soaked and cooked.

It is not so easy to buy salt cod in Britain. Your best bet is in cities where shops in residential areas cater for an ethnically mixed population. I live in an area of north London where smart restaurants and wine bars are non-existent, but at least I can easily lay my hands on salt cod.

The best quality is to be found in the Italian and Portuguese delis, but they often run out, in which case I turn to the nearby fishmonger, who sells what is proudly vaunted as the 'cheapest salt cod in north London'. You can see why; the triangles of fish are small and scrawny. It is very salty and the allocation of waste per wedge is high. Not so much of a bargain in the end. The other vendors are either the West Indian shops, or the local Safeway (this branch really does cater for its community), which sell salt cod in small packets. Again, the quality is not top-notch, but it is perfectly acceptable.

Still, if you are lucky enough to have the choice, try to buy your salt cod from a shop where they stock whole, large (a good 1 1/2 ft/0.5m long) triangular pieces. Ideally you want a piece cut from the wider upper part of the fish, where you will get a good thickness of flesh. Beware, however, of being landed with nothing but the cartilaginous and highly gelatinous 'shoulder' right at the top.

To prepare salt cod, soak it for at least 24 hours in plenty of cold water, changing the water a minimum of three times. And remember, some cod is so salty it will need 36 or even 48 hours' soaking, so be prepared. Taste a shred or two of the soaked cod to see how it is coming along.

To cook, place in a shallow pan with enough water or milk, or a mixture of the two, just to cover, adding if you wish slices of onion, a few bayleaves, and a sprig or two of parsley, and bring gently to the boil. Poach until it flakes easily - around 5-15 minutes depending on the size of the pieces.

In most salt cod dishes, the fish is then cooked again with other ingredients, so be mindful not to add any salt (it is easy to do it without thinking), until you have tasted the finished dish and are sure that it really needs it.

Salt cod fritters

Acras de morue in the French-speaking Caribbean, 'stamp and go' in Jamaica, these fritters are a gentle introduction to the flavour of salt cod. Serve them either as a snack or as a main course with a tomato sauce or spicy relish.

If you want to cook them in advance, re-heat by popping them back into hot oil for a few minutes.

Makes around 20

Ingredients: 8oz (225g) salt cod, soaked and drained

1/2 tsp fresh thyme leaves

1 1/2 tbs chopped parsley

3 spring onions, chopped

1/2 Scotch Bonnet chilli, or 1 red chilli

8oz (220g) plain flour

1/2 tbs baking powder

2 eggs, beaten

1/4 pint (150ml) or so of milk

salt and pepper

vegetable or sunflower oil for frying

Preparation: Poach the salt cod until it flakes easily. Drain well, then flake, discarding skin and bones. Process with the herbs, spring onions and chilli in short bursts until finely chopped.

Sift the flour with the baking powder, and sprinkle over the salt cod. Make a well in the middle and add the eggs. Gradually beat the eggs into the mixture, adding the milk to form a thick, sticky batter.

Heat the oil to 325F/170C and deep-fry dessertspoonfuls of the batter, pushing them carefully off the spoon into the hot oil. Cook until evenly browned, turning once. Drain briefly on kitchen paper and eat while still hot.

Bacalhau a Gomes de Sa

This Portuguese recipe for salt cod with potatoes and olives seems basic enough, but it is the most superb way of cooking salt cod that I know. It is one of those dishes that is somehow more than the sum of its parts, a blessed blend of tastes and textures, brought together with plenty of rich olive oil - do not be tempted to reduce the quantity for the sake of a few calories.

Serves 4-6

Ingredients: 1lb (450g) salt cod, soaked and drained

4 eggs

4 medium-sized potatoes, boiled in their skins

1/4 pint (150ml) olive oil

3 cloves garlic, chopped

2 large onions, chopped

20 black olives

3tbs chopped parsley

salt and pepper

Preparation: Put the salt cod and eggs into a pan and add enough water to cover. Bring to the boil and simmer for 8 minutes. Remove the eggs and check on the cod to see how it is doing. If it flakes easily, drain that, too; if not, simmer gently for a few more minutes. Drain. Flake the cod, discarding skin and bones. Shell the eggs and slice. Skin the potatoes, and cut into 1in (2.5cm) chunks.

Put the olive oil and garlic into a wide, deep frying pan and warm over a gentle heat for a minute or so, then add the onion. Cook until onion is translucent and tender, without browning. Add the flaked salt cod and stir for a minute, then add the potatoes. Continue stirring until piping hot, then stir in the parsley and pepper. Add a little salt if it is needed, but be careful as the cod may have already provided quite enough. Tip into a warm serving dish and garnish with the sliced eggs and olives. Serve immediately.

Bacalao a la vizcaina

I first heard of this Basque dish when I was trying to learn Spanish from a teach-yourself cassette. Ordering it, in the restaurant scene, was probably the most interesting part of the course. It is impossible to reproduce the authentic dish here, as it should be made with dried choricero peppers, which I have yet to see for sale in Britain. Grilled fresh red peppers change the nature of the sauce, but it still tastes very good.

Serves 4

Ingredients: 1 1/2 lb (450g) salt cod, soaked and drained

2 large red peppers, grilled and skinned

7tbs olive oil

2 large onions, chopped

2 cloves garlic, chopped

2 hard-boiled egg yolks

4oz (110g) jamon serrano, or

prosciutto, diced

2oz (55g) streaky bacon, cut into small strips

2 sprigs parsley

salt and pepper

Preparation: Poach the salt cod until it is just done, then drain. Divide it into large chunks, around 1 1/2 in (4cm) across. Reserve.

Put 6tbs of oil into a pan with the onion, garlic and parsley. Cover and stew over a very low heat for about 1 hour, stirring occasionally. The onions should not brown (if absolutely necessary, add a tablespoon of water, but they should produce enough liquid to save themselves). Process with the peppers, egg yolks and pepper. Gradually blend in about 1/4 pint (150ml) water to give a medium-thick sauce.

While the onions are cooking, saute the jamon and bacon in the remaining oil until lightly browned. Place the cod in a heat- proof dish, sprinkle over the sauteed ham and bacon and pour over the sauce. Heat gently until piping hot, taste and adjust seasoning, and serve immediately.