Recipe
Grilled Mackerel with Caper & Herb Salsa Verde
Mackerel fillets on a screaming-hot griddle until the skin blisters and crisps, served with a sharp, caper-heavy salsa verde that cuts straight through the richness of the fish. Fast, inexpensive, and one of the best things August produces.
Method
Make the salsa verde first so the flavours have time to settle. Finely chop the parsley and mint together on a board — work the knife through until the herbs are fine and beginning to clump. Add the drained capers to the board and chop these through the herb mixture. Transfer everything to a bowl. Add the mustard, grated garlic, lemon zest, lemon juice and red wine vinegar. Stir in the olive oil in a slow stream until the sauce is loose and just spoonable — it should hold together lightly but pour from a spoon. Season with salt and taste: it should be sharp, herby, and properly savoury. The capers provide most of the salt, so add carefully. Set aside.
Pat the mackerel fillets thoroughly dry with kitchen paper — any surface moisture will cause spitting and prevent the skin crisping. Using a sharp knife, score each skin with two or three shallow diagonal cuts, taking care not to cut all the way through the flesh. This stops the fillet curling as the skin contracts from the heat, so the whole surface stays in contact with the pan. Brush the skin side only with neutral oil and season with a pinch of sea salt.
Heat a griddle pan or heavy cast iron frying pan over the highest heat your hob will produce for at least 3 minutes — it should be almost smoking before the fish goes in. Place the fillets skin-side down and press each one gently with a fish slice for the first 20 seconds to ensure even contact. Cook completely undisturbed for 2–3 minutes, until the skin is blistered, deeply golden and visibly crisp, and the flesh is opaque about two-thirds of the way up the fillet.
Flip the fillets carefully with a fish slice and cook flesh-side down for 30–60 seconds only. Mackerel is a thin, fatty fillet that overcooks very quickly — the residual heat from the pan and the skin side will finish the centre. Remove immediately and rest for one minute.
Serve the mackerel skin-side up on warm plates to preserve the crispness. Spoon the salsa verde generously alongside and over the fish. Add lemon wedges for squeezing at the table.
✦ Chef's note
Mackerel is one of the most inexpensive and nutritionally rich fish available in Britain, and it's at its best from late spring through summer. Ask the fishmonger to pin-bone the fillets if you're not confident doing it yourself — a pair of tweezers and five minutes at home also works. The salsa verde here is caper-forward rather than anchovy-forward (mackerel has enough of its own depth), but a single anchovy fillet chopped through the herbs adds another layer if you want it. Leftover salsa verde is excellent the next day over cold new potatoes, with a soft-boiled egg, or stirred through warm white beans.