Start At The Counter, Not The Recipe

Walking into a good fishmonger's on a British island — a quayside shop in St Ives, a counter behind the harbour wall in Oban, a Friday van in Anglesey — is a different experience from the supermarket chiller. The fish lies on ice and glass, not sealed in plastic. The person behind the counter knows what came off which boat, when, and often the name of the skipper's dog.

That's your greatest advantage. Ask, plainly: "What's the freshest thing you've got today?" Then, "What would you take home for dinner?" You'll get a more useful answer than any recipe can give you. If the reply is "the mackerel came in this morning, the cod is from Wednesday", buy the mackerel. Freshest always wins. A lesser fish at its peak beats a glamorous one that's three days old every single time.

What To Ask And What To Look For

Good fishmongers expect questions, so ask them with confidence:

• "What came in today?" Start here and let the answer shape your meal.
• "Can you fillet it, and keep the bones?" Bones, heads and trimmings make a quick stock — freeze them if you're not using them straight away.
• "How would you cook it?" Most will tell you plainly: flour and fry it, or butter and bake it, or don't do much at all.
• "Is it bony?" Worth knowing before you plan a gentle pan-fry.

Use your eyes as well. Fillets should look glossy and translucent, not milky or dry at the edges. Fresh fish smells cleanly of the sea — briny, faintly of cucumber — never of ammonia. Whole fish should have bright, bulging eyes and scales that lie flat.

Getting It Home Without Ruining It

Fresh fish is delicate, and a warm car boot is its enemy. If you're driving back from a coastal break, ask for a bag of ice and keep the fish in a cool bag on the floor in front of the air conditioning. Eat it the day you buy it if you possibly can. Otherwise, pat it dry, wrap it loosely and keep it on a plate in the coldest part of the fridge for no more than twenty-four hours.

Take the fillets out fifteen minutes before cooking. Cold fish hits a hot pan and seizes up; room-temperature fish cooks evenly and stays tender.

Keep The Seasoning Light

This is the golden rule of cooking a delicate catch: do less. Cod, plaice, lemon sole, haddock and sea bass are not stewing steak. They don't need a marinade, a spice rub or a long list of ingredients. Salt, fat, acid and a herb is very often the whole recipe.

Pat the fillets thoroughly dry with kitchen paper — this matters more than anything else for a decent crust. Season with flaky sea salt and a little white pepper just before the fish goes into the pan, not an hour before, or the salt will draw out moisture and leave you with a pale, wet fillet.

Avoid heavy coatings. A light dusting of plain flour on white fish helps it colour without steaming. For mackerel, herring or sardines — oily, robust and brilliant value — no flour is needed at all; the skin crisps beautifully on its own.

Butter, Lemon And A Locally Grown Herb

Warm a heavy frying pan over a medium-high heat and add a knob of butter with a teaspoon of oil to stop it burning. Lay the fillet in skin-side down and leave it alone. Resist prodding. For a fillet around two centimetres thick, three to four minutes on the skin side is usually right, then flip and cook for a further minute. The fish is done when it turns opaque and flakes when nudged with a fork at its thickest point. If in doubt, take it out early — it carries on cooking in its own heat.

Now the butter. Tilt the pan, spoon the foaming butter over the fish, and add a squeeze of lemon at the very end, off the heat, so the juice doesn't turn the sauce bitter. Throw in a small handful of soft herbs: flat-leaf parsley, dill, chives, chervil, or the feathery fronds from a fennel bulb. If you're near the coast, look for samphire, sea purslane or wild fennel — they grow within sight of the water and taste of it. Grated lemon zest is lovely on plaice and lemon sole. Brown butter, a few capers and lemon is the whole of a classic sole meunière, and it takes four minutes.

What To Put On The Plate

Keep the sides plain so the fish is the point. New potatoes with butter and mint, a slice of good bread, or simply a green salad dressed with lemon and olive oil. Mackerel welcomes something sharp to cut the richness — pickled cucumber, a spoonful of rhubarb chutney, a squeeze of grapefruit. Crab claw meat needs only mayonnaise, brown bread and lemon. Scallops want nothing more than hot butter and thirty seconds a side.

Serve straight from the pan, on warm plates, with the rest of the lemon on the table. That's the whole trick: buy the freshest thing in the shop, season it lightly, cook it quickly, and let the coast do the rest of the work.