Why Mackerel Deserves a Place in Your Coastal Kitchen

Mackerel is the fish that rewards anyone lucky enough to live near the sea. It is cheap, abundant in British waters through the summer and autumn, and rich enough in oil that it practically cooks itself. The flesh is dark, sweet and forgiving, and it takes to herbs and lemon in a way that few other fish do. If you have spent the afternoon walking a headland or messing about in a dinghy, this is the supper you want: twenty minutes of work, one hot grill or a hot oven, and a plate of buttery new potatoes alongside.

The catch is freshness. Mackerel is a fatty fish, and it turns quickly. Buy it the day you cook it if you can, ideally from a quayside seller or a fishmonger who can tell you when it came off the boat. Look for bright, slightly bulging eyes, shiny skin with clearly defined stripes, and a body that is stiff rather than floppy. It should smell of the sea and nothing else. If you catch your own, gut it on the beach, rinse it in seawater and get it on ice or in a cool box as fast as possible.

Getting the Fish Ready

Ask your fishmonger to gut, de-scale and remove the head if you like — many people prefer mackerel without the head for roasting, as it fits a tray better. Otherwise, do it yourself at the sink. Run a sharp knife from vent to gills, pull out the innards, and rinse the cavity under cold water. The dark line along the inside of the spine is blood; scrape it away with a thumbnail or the back of a knife, as it tastes bitter.

Next, score the fish. Make three or four shallow diagonal cuts through the skin on each side, about a centimetre deep at most. This does two jobs: it stops the skin curling and splitting under fierce heat, and it lets the herb and lemon flavours get past the skin and into the flesh. Pat the fish dry inside and out with kitchen paper, then season the cavity with salt and black pepper.

• Size guide: one fish of 300–400g is a generous single portion; smaller ones at 200–250g mean two per person.
• Timing: cook within 24 hours of buying for the sweetest flavour.
• Kit: a shallow roasting tin lined with baking parchment, or a grill pan with a rack, keeps the skin intact.

The Herb and Lemon Mix

Keep this simple and green. For two large fish, mash together 50g of softened butter with three tablespoons of finely chopped flat-leaf parsley, one tablespoon of snipped chives, the finely grated zest of one lemon, a good pinch of sea salt and a twist of pepper. If you would rather not use butter, use three tablespoons of mild olive oil or rapeseed oil instead and stir the herbs through it.

Push half of this mixture into the cavities of the fish, then lay two or three thin slices of lemon inside each one. Rub the remaining herb butter over the scored skin, working it into the cuts. Leave the fish to sit for ten minutes at room temperature while you heat the grill or oven — cold fish straight from the fridge will cook unevenly.

Two Ways to Cook It

Under the grill. Set the grill to its highest setting and let it come up to full heat for five minutes. Place the fish on a rack about 10cm from the element. Grill for four to five minutes on the first side, until the skin blisters and darkens in patches, then turn carefully with a fish slice or two spatulas. Give it another four minutes. The flesh should be opaque right to the bone and flake easily when nudged with a knife. Mackerel is best slightly underdone rather than dry.

In the oven. Heat the oven to 200°C fan, 220°C conventional, gas mark 7. Lay the fish in a lined roasting tin, spoon over any remaining herb mixture, and roast for 16 to 20 minutes for large fish, 12 to 14 for small ones. Baste once halfway through with the buttery juices in the tin. If you have a barbecue going, wrap each fish in lightly oiled foil with its herbs and lemon and cook over medium coals for about eight minutes a side — the smell alone is worth it.

New Potatoes and the Rest of the Plate

Put 700g of new potatoes in a pan of well-salted water and bring to the boil. Simmer for 15 to 18 minutes, until a knife slides in without resistance, then drain and toss with a knob of butter and a handful of chopped chives or mint. If you have wild garlic or sea beet growing nearby, a few shredded leaves stirred through the warm potatoes are excellent.

Beyond the potatoes, keep things sharp and unfussy:

• Salad: rocket or watercress with a lemon and rapeseed oil dressing.
• Something acidic: a dish of plain yoghurt with lemon juice, or a spoonful of horseradish crème fraîche.
• Bread: thick slices of sourdough to mop up the pan juices.
• To drink: a dry cider, a crisp white or simply cold water with lemon.

Serving, Bones and Leftovers

Slide a knife along the backbone and lift the top fillet away in one piece, then ease out the backbone and any fine pin bones with your fingers or tweezers. The flesh nearest the tail is fine-boned, so eat that part with care. Any leftover mackerel flakes beautifully into a salad the next day, or mash it with a little mustard and lemon and spread it on toast.

Cooked this way, mackerel tastes of the coast it came from: salty skin, sweet flesh, herbs and lemon cutting through the oil. It is the sort of supper that asks nothing of you but a sharp knife, a hot grill and an appetite earned outdoors.