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.

NATHAN OUTLAW’S FISH KITCHEN published by Quadrille (£20)