Saint Peter’s crisp-skinned Spanish mackerel, aïoli, parsley and pickled onion salad

1.For aioli, process yolk, mustard and vinegar together in a small food processor. With motor running, slowly add oil in a thin steady stream and process until thick and emulsified. Add lemon juice, garlic and salt to taste. Refrigerate until required (this can be done a day ahead).

2.For parsley salad, halve onions and slice into half-moons. Combine in a bowl with parsley, drizzle with olive oil, lemon juice to taste and a little of the pickling liquid from the onions, and toss to combine.

3.Preheat oven to 200C. Heat a deep ovenproof frying pan over high heat. Add clarified butter and heat until a light haze is visible on the surface. Very lightly dust skin side of fillets with rice flour and tap to remove excess. Place fish in pan skin-side down, lowering it away from yourself to avoid burns. Place a square of baking paper on top of the fish, then a heavy saucepan on top of that to weight the fish down –this helps ensure the skin crisps and fish cooks evenly; cook until skin is golden (2 minutes). Remove saucepan and place frying pan in oven until the fish’s flesh is warm to touch (2 minutes). Remove from oven, turn fish over so it’s flesh-side down in the hot pan, then immediately remove fish to a warm plate to rest for a minute. Slice fillets in half and place on serving plates with a dollop of aioli and pile of parsley salad.