Grilled Mackerel with Caramelised Apples

Pat the butterflied mackerel completely dry with kitchen paper, then score the skin of each fillet three times on a diagonal with a sharp knife. Season flesh and skin generously with the flaky salt and black pepper. Brush the skin side lightly with olive oil.

Rest the seasoned fish uncovered at room temperature for 15 minutes to allow the salt to draw out surface moisture.

Place a heavy-based skillet or cast-iron pan over medium heat and add the butter. Cook, swirling frequently, for 3–4 minutes until the butter turns golden and smells of toasted hazelnuts — do not let it blacken.

Add the shallot to the brown butter and cook, stirring, for 2 minutes until softened and translucent.

Add the apple wedges in a single layer and cook undisturbed for 4 minutes until the undersides are deep golden and caramelised.

Flip the apple wedges, scatter over the brown sugar and thyme, and cook for a further 3 minutes until the apples are just tender but holding their shape.

Add the cider vinegar to the pan and stir for 30 seconds, scraping up any caramelised bits from the base, then remove from heat and stir through the Dijon mustard and crème fraîche until combined. Keep warm.

Preheat your grill to its highest setting, or heat a ridged cast-iron grill pan over high heat until smoking. Brush the grill rack or pan with a little olive oil.

Place the mackerel skin-side up under the overhead grill, or skin-side down on the grill pan, and cook for 5 minutes until the skin is blistered and charred at the edges and the flesh is opaque all the way through — use a meat thermometer to confirm an internal temperature of 63°C at the thickest part.

Spoon the caramelised apple mixture onto warmed plates, lay a grilled mackerel over each portion, scatter with flat-leaf parsley, and serve immediately with lemon wedges alongside.