Salt-baked Cornish turbot with new potatoes, broad beans and spinach

Serves 6-8

10kg/22lb rock salt (not sea salt)
1 whole turbot, weighing approximately 2 kg/5 lb, gutted but left whole
600g/1¼lb little new potatoes
200g/7oz freshly podded broad beans
150g/5oz young-leaf spinach

For the mayonnaise

3 egg yolks
Juice of 1 lemon
2 tsp Dijon mustard
Sea salt and freshly ground black pepper
200ml/7fl oz extra-virgin olive oil

Pre-heat the oven to 180C/350F/Gas 4 and pour the rock salt into a mixing bowl. Using your hand to combine, add enough water to give the consistency of wet sand (as much as a litre, depending on the type of salt).

Spread half of the salt-mix evenly on a baking tray, laying the fish on top. Cover with the rest of the salt and tightly pack in the fish as if you were burying someone at the beach. Place in the middle shelf of the oven and bake for 20 minutes.

Remove the fish from the oven and allow to rest for a few minutes. You can test whether the fish is cooked by piercing the thickest part through to the bone with a sharp knife. If the knife tip feels warm to the touch, the fish is ready. To serve, crack the salt crust, carefully peel off the skin, and discard.

While the fish is cooking, make the mayonnaise. Place the egg yolks in a food processor and add the lemon juice, mustard and a good pinch of salt and pepper and whiz briefly to combine. Next, with the motor running, pour the olive oil slowly into the funnel until it is all incorporated and the mayonnaise has a glossy sheen.

Once that is done, cook the potatoes in well-salted boiling water until tender, for about 10-15 minutes. At the same time, bring a separate pan of water to the boil and add the broad beans. Allow the water to come back to the boil and cook for 45 seconds. Remove the beans and refresh under cold water. When cool, slip off the dull grey skins to reveal the lime-green bean inside.

While the fish is resting, place the washed spinach leaves in a large saucepan and cook over a high heat until just wilted (this will take no longer than a minute) then drain.

Serve the succulent fish flesh in large chunks drizzled with the mayonnaise and the seasonal vegetables.