Mackerel is an oily-fleshed sea fish found throughout the oceans of the world. The flesh is strong-flavoured and the fish is bony, which means it is not a fish for beginners.
It is important to buy mackerel as fresh as possible. If you can, buy it with the head on, so that you can see if the eye is still bright; if it isn't, don't buy it.
One way of cooking mackerel is to chop off the head and gut the fish, then make up a paste of mustard, lemon juice, garlic and rosemary. Make some incisions into the side of the fish, then rub the paste over the skin of the fish, working it into the cuts. Fill the body cavity with finely chopped onion and herbs. Wrap the fish in foil and bake it in a preheated medium oven for about 20 minutes. Serve with boiled potatoes.
Smoked mackerel can be bought in most supermarkets and fishmongers and is often served with a salad.