• 1 turbot, weighing 1.5–2 kg (3 lb 5 oz–4 lb 8 oz)
• 2 tablespoons olive oil
• 1 lemon
• a few sprigs of marjoram or thyme
• 125 g (4½ oz) unsalted butter
• 3 egg yolks
• 2 tablespoons white wine
• sea salt and black pepper

Preheat the oven to 220°C (425°F, Gas Mark 7).

Make sure that the gills and innards of the fish have been removed and rinse the fish in cold water. Season the cavity with sea salt. Pour 1 tablespoon of the olive oil and sprinkle some sea salt onto a roasting tray and lay the fish on top. Sprinkle with more salt, a grinding of pepper and the remaining olive oil. Place in the oven and bake for 15–20 minutes. The fish should be very slightly undercooked and at the point where the fillets at the tail end just begin to separate. Cover the fish with foil and keep warm in a low oven.

Peel the zest from the lemon and cut into very thin strips. Drop these into a pan of hot water for a few seconds, then refresh in cold water. Pick a teaspoon of marjoram leaves but do not chop them.

Melt the butter in a small saucepan and keep warm. Whisk the egg yolks with the white wine, the juice of the lemon, plenty of freshly ground black pepper and a pinch of salt in a small heatproof bowl. Place the bowl over a small pan of simmering water and whisk over a low heat. It takes a while before the mixture becomes foamy, thickens, aerates and turns into a ‘sabayon’, which leaves a trail or ribbon behind itself. Whisking all the time, trickle in the melted butter, adding the milky residue at the bottom of the pan if the sauce becomes too thick. Once the butter has all been added, check the seasoning and keep the hollandaise in a bowl in a warm, but not hot, place.

Sprinkle the fish with the lemon zest and marjoram leaves and baste with the juices that have collected in the tin. Serve with the hollandaise, a green vegetable and some plain boiled new potatoes.