You can still eat cod, if you buy sustainably and use the whole fish

I must say that I'm slightly bored of scratching around for sustainable species of fish that I know are going to be so over-promoted that they're probably going to become unsustainable themselves – just as hoki did a few years back. Menus and food columns are all "pollack this" and "pollack that" these days and I realise that I'm probably one of the guilty parties because I was one of the people writing about the species years ago.

Although you don't see that much pollack on the fish displays, you do still see a lot of cod – which ideally should be Marine Stewardship Council-certified, Pacific cod from Alaska or from areas which are fished sustainably. If you have to buy north-east Atlantic cod, try to choose north-east Arctic cod. And wherever you buy your cod from, make sure it's line-caught. If you live near the coast, don't forget the smaller boats that fish close to shore and occasionally land the odd cod to sell direct from their boat.

Now, should we really stop using one of our best-loved fish because it is being used and abused, or is it time to stop and have a good think about it? One thing that is very important to me is what happens to the rest of the fish.

I believe in buying whole or part of the fish, and then using the bones for a soup or stock and the tails and belly and cheeks for a pie or fishcakes or a homemade brandade. In France and Spain they utilise everything from the tongue to the belly and even the tripe.

It's easy to blame the fishermen for depleting the fish stocks by over-fishing but if we and the supermarkets were a little more economical about what we buy and sell, there would be more cod to go around.

How to prepare a cod

You can tackle cod in various ways, depending on the size of your fish and how many of you are eating. First, remove the head by cutting behind the gills at an angle towards the head so that no meat is wasted. With the point of a very sharp knife, cut out the cheeks and lay on a tray. Cut away the collar (top, centre) that covers the gills and cut it in half if it's a large cod. With a heavy knife, cut the head in half and remove the tongue.

Now you can either fillet the cod or cut thick steaks (top left) through the bone. For steaks, first cut away the uneven flesh to straighten it up where you removed the head and put to one side with the bones and the head. Then cut thick steaks through the bone about 3-4cm thick; they should weigh about 300g each. Fillet off the tail (above), remove skin and keep the flesh along with the rest of the offcuts, the bones and head.

Cod, potato and leek soup

Serves 4-6

This is a delicious, fishy winter warmer and it costs virtually nothing. You will be amazed how much meat you can get from the head once it's been cooked and the gelatinous stock gives the soup a lovely velvety texture.

1 cod's head, halved
1 large onion, peeled, halved and roughly chopped
1 large leek, roughly chopped and washed
10 cloves of garlic, roughly chopped
1 large floury potato, peeled and roughly chopped
Stalks from the parsley
2 litres fish stock
10 white peppercorns
A glass of white wine
Salt and freshly ground black pepper

For the garnish

1 large leek, halved, cut into rough 2cm chunks and washed
1 large potato, peeled, thinly sliced and cut into rough 2cm squares
2tbsp chopped parsley
3-4tbsp double cream

Put all of the ingredients for the soup in a large saucepan, bring to the boil, season and simmer for 30 minutes. Remove the head and leave to cool a little, leaving the soup to simmer. Remove as much meat from the head as possible and return the bones to the pan. Simmer the soup, skimming and stirring every so often, until the potatoes have disintegrated and thicken the soup.

Strain the soup through a fine-meshed sieve into a clean saucepan, pushing as much through the sieve as possible with the back of a ladle.

Add the second leek to the soup and simmer for about 10 minutes then add the potato. Continue simmering until the potatoes and leek are cooked. Add the parsley, cream and cod meat and simmer for a couple more minutes. Season to taste and serve.

Roast cod with cockles, cider and parsley

Serves 4

A nice chunk of cod cooked on the bone is a comforting thing, and we seem to have moved away from good old-fashioned cod steaks or cutlets to nicely trimmed cod loins – but do cods really have loins? I don't think any fisherman would say so.

Fresh cockles are becoming much more popular now, thankfully, but they do need careful preparation, as they tend to be gritty.

Leave them in a bowl of cold water for about 30 minutes, agitating them with your hand every so often to loosen sand from the tiny grooves on the shells. Repeat this with fresh water after half an hour.

4 cod cutlets or steaks weighing about 250-300g
3 large shallots, peeled, halved and finely chopped
100g butter
500g cockles, washed
250ml dry cider
200ml double cream
2tbsp chopped parsley
Salt and freshly ground black pepper

Pre-heat the oven to 220/gas mark 7. Season the cod steaks, place on a roasting tray and rub with butter. Bake for about 15 minutes, checking if the middle is hot by inserting the point of a sharp knife near the centre bone.

Meanwhile, give the cockles a good rinse and drain them. Gently cook the shallots (in a large pan) for a minute or so, add the cockles and cider, cover and cook on a medium heat for 4-5 minutes, shaking the pan every so often, until all of the cockles are just open.

Remove the pan from the heat and pour the liquid into another pan. Boil on a high heat for a few minutes until it has reduced by about two-thirds. Add the cream and parsley and continue boiling until it has reduced by half. Add the sauce back to the cockles and re-heat for a minute or so. Serve the cod in soup bowls with the cockles scattered around.

Salt cod fritters

Serves 4

Depending how much fillet you have left will obviously decide how many fritters you can make. Either way, this is a great way to use up tail ends, etc, for tasty little snacks. You can even mould these with a teaspoon and make little canapé-sized nibbles to have with drinks.

About 500g cod fillet, skinned
120-150g coarse rock or sea salt
1 bay leaf
2 medium-sized floury potatoes, peeled and cut into chunks
2tbsp olive oil
300ml milk
50g plain flour
3 medium eggs, beaten
3 garlic cloves, peeled and crushed
1tbsp chopped flat leaf parsley
Vegetable or corn oil for deep frying

The day before, place the cod in a non-reactive bowl and cover with salt and leave overnight in the fridge. The next day rinse it off and soak in cold water for a couple of hours, changing the water a couple of times.

Put the cod into a pan with the bay leaf, cover with water and simmer for 10 minutes. Remove the cod from the pan with a slotted spoon and leave to cool on a plate. Add the potatoes and cook for 10 minutes or so until tender, and drain. Return to the pan on a low heat for a minute or so to let any excess water evaporate. Put the milk and olive oil into a pan and bring to the boil, then remove from the heat and slowly mix in the flour with a wooden spoon until smooth. Leave to cool slightly then gradually beat in the eggs until smooth. Mash the potatoes and mix into the milk mixture with the cod, garlic and parsley. Try not to break up the cod too much, it needs to have a bit of texture. Season to taste and leave to cool for an hour or so. Pre-heat about 8cm of oil to 160-180C in a large, thick-bottomed saucepan or electric deep-fat fryer. Using a dessert spoon, scoop rough shapes of the mix and drop into the fryer and cook for 2-3 minutes, turning them with a slotted spoon while cooking until nicely coloured, then drain on some kitchen paper.

Serve as they are or with lemon or aioli or a garlicky mayonnaise.

Cod bits with butter beans and bacon

Serves 2-4

Those bits and bobs of cod that normally get thrown away can be turned into something special. You should have left the tongue, cheeks and collar.

The tongue, cheeks and collar from the cod
1 medium onion, peeled, finely chopped
A couple of good knobs of butter
60g bacon, rind removed and cut into rough 1cm chunks
Half a glass of white wine
About 150ml of the cod soup
100g good quality canned butter beans, drained and rinsed in cold water
1tbsp parsley
Salt and freshly ground white pepper

Put the bacon in a pan, cover with water, bring to the boil and simmer for a couple of minutes, then drain. Season the cod bits, melt the butter in a heavy-based saucepan and fry them on a medium heat for 3-4 minutes, turning them until lightly coloured. Remove from the pan and put to one side. Add the onions and bacon to the pan and cook on a low heat for a couple of minutes without colouring, then add the white wine and simmer until completely reduced. Add the soup, butter beans and the tongues and simmer gently for about 10 minutes with a lid on. Add the cheeks and collar and simmer for another 3-4 minutes, then add the parsley and season to taste. Add a little water if the sauce is becoming dry and simmer gently for a couple more minutes. Serve as it is as a starter or with some toast.