Preparing fish and shellfish

Preparing fish and shellfish

Nathan Outlaw
0 recipes
Published by
Quadrille Publishing
David Loftus

Filleting a flat fish

A flat fish yields four fillets and has two distinct sides. The top side displays the individual characteristics of the species – the orange spots of a plaice, or the lumpy skin of a turbot, for example. The underside should be a clean, creamy white. Make sure the fish has been gutted and is as dry as possible. Unless you’ve caught the fish yourself, it will most likely be gutted. If not, it’s straightforward to do.

Before you start filleting, make sure your chopping board is secure by placing a damp cloth underneath it to stop it slipping. A razor-sharp knife is equally important; a blunt knife will slip and is therefore dangerous.

Lay the fish on the chopping board with the head pointing away from you. Insert your knife at the side of the head and bring it around to the centre of the neck. Now run the knife down the centre bone to the end of the tail, in one straight line. Then, starting from the cut at the bottom of the head, carefully cut the fillet free from the skeleton, holding the knife flat against the bones and working towards the edge of the fish.

When you have freed all the flesh from the bone, cut through the skin at the tail end and work up the edge of the fish until you reach the top where you originally started. You should now have released the first fillet.

To remove the second fillet, turn the fish around so the head is pointing towards you. Starting from the tail and working up, do exactly the same as before until the fillet is released. Turn the fish over and repeat on the other side to release the other two fillets.

Skinning a flat fish fillet

Make sure your chopping board is secure and your knife is sharp. Lay the fillet skin side down on the board and trim away the skirt from the outer edge. (You’ll find it much easier to skin the fillet if you do this first.) Now, holding the tail end down with one hand, slightly angle your knife down towards the board. Using the length of the knife and cutting smoothly, run the knife along the skin to release the fillet from it.

The aim is to leave as little flesh on the skin as possible, if any! Sometimes little bits of skin are left on the flesh, but you can just trim these away carefully.

Preparing a flat fish to cook whole

First make sure the fish has been gutted and is free from scales and sea slime. If the guts are still in place you’ll find them easy to remove. They are situated just below the head and pectoral fin, so feel around with your fingers until you locate the soft innards.

Make a semi-circular cut around the edge of the gut cavity, insert your fingers into the cavity and pull the guts out. Rinse the cavity well. Now, using strong scissors, trim away the skirt from around the edge of the fish. Cut off all the fins and trim the tail.

On bigger fish like turbot you may want to remove the gills and skin, but I don’t bother. I know I’m not going to eat the gills, so they do not offend me and I like to keep the skin on as it gives the fish some protection during cooking.

Tranching a flat fish

This is the best way to cook a big flat fish. You will need a sharp large cook’s knife, kitchen scissors and a rubber mallet or old rolling pin that you don’t mind getting dented.

Lay the fish on a chopping board. Remove the skirt and fins, then cut around the head and remove it. Using the cook’s knife, make a slice along the central bone from the head to the tail. The aim is to cut through this bone, so try to get the knife as central as possible. Use the mallet to give the knife a firm tap and it should go through the bone, leaving you two clean sides of fish. Next, turn the sides around and mark out the size of portion you want, slicing down to the bone at the point where you want to cut it. Obviously, you will need to adjust the intervals of your cuts, making them wider towards the tail end, to give roughly equal-sized portions.

Again hold the knife firmly against the exposed bone and hit it hard with the mallet to give you a clean quick cut. You now have a tranche ready for cooking. Repeat to cut the rest of your tranches.

Tranching is only suitable for bigger flat fish, such as turbot and brill, which yield fairly chunky portions.

Descaling round fish

If you plan on eating your fish with the skin on – which is deliciously crisp after grilling, frying or roasting – you’ll want to descale it. Most of the fish you buy will have been descaled already, or your fishmonger will offer to do it for you, but should you need to descale it yourself, it really isn’t difficult. It’s easiest to descale a fish when whole and to do so underwater, as this stops the scales from flying all over your kitchen.

Fill your sink with enough water to cover the fish. Now, holding the fish by the tail, submerge it in the water. Using a descaler or the back of a knife, push firmly against the skin from the tail to the head (i.e. in the opposite direction to the way the scales lie) and the scales will come off. Make sure you are careful not to push too hard as this will crush the flesh. Turn the fish over and repeat on the other side. When all the scales are off, wash and dry the fish, checking for any stray scales. It is then ready to use.

Steaking a round fish

Certain round fish really benefit from being cooked on the bone as steaks, because it seems to keep the texture firm and the fish moist – great for braising in a stew, for example.

Using a very sharp, strong knife, mark the fish at intervals where you want to portion it, then slice straight through, using a mallet to force the knife through the bone if necessary. Make sure that the portions are equal or they won’t cook evenly.

Filleting a round fish

A round fish yields two fillets. Make sure the fish has been descaled and gutted, and that all the fins and scales have been removed. Use a large chopping board and make sure it is firmly secure on your worktop by placing a damp cloth underneath it, and that your knife is very sharp.

Lay the fish on the board with the belly facing away from you. Make a cut at the tail end and bring the knife up along the fish, just above the backbone to the head (this cut only needs to be a few centimetres deep). When you reach the head end, cut across the fish diagonally just behind the gills, just as far as the skeleton. Now, in a firm, sweeping motion, work the knife flat across the bones from the tail to the head end, to ease the fillet away. Cut through the flesh at the tail end to release the fillet and carefully work it away from the rib cage.

To remove the second fillet you need to turn the fish over and follow the same procedure, but working from the head down to the tail. So, start by making an incision at the head end and make a shallow cut along the backbone, just above it, down to the tail.

Now carefully skim the knife over the skeleton, working smoothly from head to tail. Cut through the fillet at the head end to release the fillet and carefully work it away from the rib cage until it is free. You will now have two fillets and a clean skeleton.


Pin bones are not something that you want to get stuck in your throat, so it’s always best to remove them, and is very easy to do. Lay the fish fillet on your chopping board, flesh side up. Using your fingers as a guide, feel along the centre of the fillet for any small bones. With a pair of strong tweezers, grab hold of any pin bone you find and pull firmly – towards the end where the head would have been – to remove it.

Skinning a round fish fillet

To skin the fillet make sure your board is secure and your knife is sharp. Lay the fillet in front of you and trim the outer edge to neaten. Now, firmly holding the skin at the tail end with one hand, slightly angle your knife down towards the board, so that when you cut into the fillet the knife will run along the skin and won’t cut into the fish. Use the length of your knife as you move the knife over the skin to release the fillet from it, and avoid being aggressive with your movements. Sometimes little bits of skin get left on the fillet; just trim these off carefully.

Preparing a round fish to cook whole

To gut the fish, if necessary, hold it belly side up in one hand with the head pointing away from you. Insert the tip of the knife at the anal vent and make a shallow cut through the flesh along the belly and up to the throat to open up the cavity. Using your hand, pull out all the guts from inside. You really do need to take care as you do this, as there may be sharp hooks and/or little spiny fish caught inside. Rinse the cavity well. Now, using strong scissors, remove all the fins and trim the tail. Cut out the gills, too. Leave the skin in place to protect the fish during cooking.

Butterflying fish

This is a particularly good technique for smaller round fish, such as sardines, herring and small red mullet. If necessary, remove the guts and cut off the head, fins and gills. Extend the cut from gutting the fish so the fish is opened from top to tail end.

Now cut down both sides of the skeleton to release the flesh, without cutting right through. Using the palm of your hand, gently push down onto the back of the fish until the backbone is flat against the chopping board and the fillets are either side.

With most fish, you can simply pull out the backbone with your fingers, but if that isn’t possible, use strong scissors and then trim off the backbone. Now use a filleting knife to trim the fish neatly and pin-bone using tweezers. The butterflied fish is now ready to cook.

Preparing monkfish

Filleting monkfish is easier than other fish because it has only one central bone that runs along its entire length, but first you need to remove the skin. Take your monkfish tail and release the skin at the head end with your knife. Grasp this skin and pull towards the tail end with some force to remove the skin in one piece.

Now to fillet the monkfish, take a sharp knife and run it along one side of the bone, leaving no flesh behind on the bone. Repeat on the other side of the bone. You now have your two monkfish fillets.

Monkfish also has an inedible tough outer membrane that must be removed. As if you were skinning the fillet, grab a small bit of flesh at the tail end and cut into it. Now, holding the tail end with one hand, bring the knife from the tail to the thick end, removing as much of the membrane as possible.

Turn the fillet over and you’ll expose the thin sinew in the red bloodline running along the fillet. Using the tip of your knife, cut this out. Trim off any remaining membrane. Your fish is now ready to cook.

Cooking lobster

It is possible to kill a live lobster instantly by holding it firmly, plunging a knife into the cross on its head and splitting it lengthways quickly in two, but in reality it’s quite hard to kill it with one blow. Instead I prefer to calm this crustacean first, rendering it almost comatose. The lobster may be a simple creature, with a long nerve cord rather than a brain, but it still deserves to be treated humanely.

Before boiling, I put the lobster in the freezer for about an hour until it’s calmed to the point of hardly moving. Then I have a big pan of fast-boiling well-salted water ready. Use 30 g salt to 1 litre water.

To cook the lobster, take it from the freezer, place it on a board and firmly insert the tip of a strong knife into the cross on the head to kill it instantly, then plunge it straight into the boiling water. Bring back to the boil. From this point, I allow 10 minutes for a lobster weighing 700 g and add 1 minute for every 100 g above that. For a smaller 500–600 g lobster, I allow 8 minutes. When the cooking time is up, lift out the lobster and place it on a tray to cool.

Preparing lobster

When the lobster is cool enough to handle, you can extract the meat. Lay it on your chopping board and split it in half lengthways from head to tail, using a large, heavy knife.

Remove the small stomach sac in the head and the dark intestinal tract that runs along the length of the tail. Don’t discard the liver or ‘tomalley’, which is delicious. The red coral in female lobsters is good to eat too.

Tap the claws firmly with the back of a heavy knife to crack them open and release the meat. You can also pull out the meat from the thin legs.

Cooking crab

I put crabs into the freezer an hour or so before cooking to calm them down. Also, I always try to cook my crabs in sea water, but you can use 30 g salt to 1 litre tap water. If there is not enough salt in the water, flavour will leach out from the crab into the water. Bring your salty water to a fast boil.

Take the crab from the freezer and plunge an awl or other sharp pointed tool into one of the two points on its underside to kill it instantly, then plunge it into the boiling water. Once the water comes back to the boil, cook for 15 minutes if the crab is 1 kg or less, adding 2 minutes for every extra 100 g. As soon as the crab is cooked, lift it out onto a tray and leave until cool enough to handle.

Preparing crab

Remove all the legs and claws from the cooked crab, by twisting them away from the body. Now, holding the crab in both hands, use your thumbs to push the body up and out of the hard top shell.

Remove the dead man’s fingers, stomach sac and hard membranes from the body shell. Using a spoon, remove the brown crab from the top shell and place in a bowl. Now cut the body in half with a sharp knife to reveal all the little channels of white crab meat. Use a crab pick or the back of a spoon to pick out all the crab meat from these crevices and put it into a bowl.

Now, with a heavy knife, break each claw with one hard tap if possible and pick out the crab meat, removing the cartilage in the middle of the claw. Do the same to extract the meat from the legs.

When you have taken out all the crab meat, go through it very carefully with your fingers a couple of times to check for any stray fragments of shell or membrane.

Opening oysters

I find an oyster knife isn’t the best implement for shucking an oyster unless you’ve one with a small blade; I prefer to use a sturdy butter-knife-sized knife.

Hold the oyster flat side up in a folded tea towel (for protection), in one hand. Insert the knife into the hinge of the oyster and wiggle at the hinge, using a little force, until you hear a popping sound and it yields. Run the knife along the roof of the flat side to cut the attaching muscle and release the oyster from the top shell.

Using the same knife, carefully cut away the same muscle from the bottom shell and turn the oyster over in the shell, being careful to retain all the juices. The oyster is now ready.

Preparing razor clams

These tasty bivalves must always be live when cooked. Rinse well, then steam them open in a covered pan with a little white wine or water. Allow to cool slightly before pulling the clams from their shells.

Now, to prepare them, cut the longer part of the clam away from the dark sac. Then cut off the rounder end, the other side of the sac. Remove the wing-like covering from the body and scrape off any sand. You can now slice both of these parts into small slices or keep them whole. Discard the dark sac.

Opening scallops

This is a fun task once you get the hang of it. Make sure your scallops are alive – either tightly shut or ready to close when firmly tapped.

To open, hold the scallop firmly between the fingers and thumb of one hand, so the flatter side of the scallop shell is facing upwards. Insert the tip of a strong, fairly small knife between the shells at the corner of the hinge and twist to break it. Now bring the knife down between the shells to separate them and pull off the top shell. Using a thin, fairly flat spoon, scrape around the scallop and the other bits until you release everything from the shell.

Now grab the scallop, roe and skirt with your hands and find the white muscle. Use your thumb and forefinger to release the scallop meat from the muscle. Work around the scallop, carefully removing the very thin membrane until you have in your hand just the white scallop meat. The plump, bright orange coral, which comes away with the muscle, can be cut free and cooked with the white scallop.

Preparing squid

Make sure your squid is clean and white, with no pink tinges. Holding the body in one hand, grab the head and pull it firmly and carefully – the innards that are attached to it will come away with it. If the squid hasn’t released its ink already, you’ll find the ink sac within the innards.

Pull the fins or ‘wings’ away from the sides of the body. Now remove the purplish skin covering the body. Carefully scrape the body and fins with your knife to remove any ink or excess skin and give the fins a quick rinse.

Returning to the head, take hold of the tentacles and squeeze the head to remove the sharp beak, pulling it out. Using a sharp knife, cut the tentacles away from the head, just under the eyes. Rinse the tentacles.

Finally, pull out the plastic-looking quill from the body and any other insides that look as though they shouldn’t be there. Give the body a quick rinse. At this point you can cut the squid body open or slice it into rings. The fins can also be cut into smaller pieces. Cook the body, fins and tentacles as required.

Preparing cuttlefish

Using a sharp knife, cut through the hard part at the base of the head to release the cuttlebone. With your fingers, carefully push out the cuttlebone (akin to the squid’s transparent quill).

Separate the head and tentacles from the body, pulling the head firmly (as you would for squid but expect more of the innards to remain inside the body). Now cautiously reach inside the body with your hand to release the innards, taking great care to avoid rupturing the ink sac if it is still intact, otherwise you will end up in a dreadful mess!

Returning to the head, squeeze out the beak and cut off the tentacles at the eyes. Finally peel away the skin from the body – you will find this quite easy to do.

Cuttlefish can be cooked in the same way as squid, though I much prefer to braise them slowly to tenderise their thicker, tougher flesh.

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