Seaweed butter-baked cod with pea and lettuce fricassee, potatoes and mint hollandaise

For the Hollandaise, whisk together the egg yolks, lemon juice, cider vinegar and seasoning in a bowl set over a pan of simmering water. Whisk until the mixture thickens, for about 10 minutes. (To make sure the sauce doesn't overheat, take it on and off the heat while you whisk. The aim is to achieve a golden, airy sauce that forms ribbons)

Warm the rapeseed oil in a small pan, then set aside. Off the heat, gradually whisk a small amount of the warmed oil into the egg mixture, a drop at a time, then return the bowl to a gentle heat to cook a little more

Remove from the heat again and whisk in another dash of warm oil. Repeat until all the oil is incorporated and the sauce has a thick, mayonnaise-like consistency

Season with salt and pepper to taste, plus 2–3 tablespoons of warm water to give the sauce a pouring consistency. Stir through the chopped mint and keep warm over the bain marie

Sprinkle a tray lightly with sea salt and place the cod portions on top. Cover lightly with more sea salt and allow to cure for 8 minutes

Meanwhile, place the potatoes, salt, mint and lemon in a large pan and cover with cold water. Place on a high heat and bring to the boil, then turn down the heat and the simmer potatoes until just-cooked

Remove the potatoes from the heat, strain, and place in a bowl with the butter or oil. Season with sea salt and white pepper, mix well and cover. Set aside to rest for 10 minutes

Preheat the oven to 180°C/gas mark 4

To make the seaweed butter, simply mix together the butter and kombu powder

Rinse the salt from the cod and pat-dry with kitchen paper. Spread the salted butter on a baking tray and place the portions of cod on top. Divide the seaweed butter into four and place on top of the cod. Bake for 8–10 minutes, or until the cod is just-cooked. Remove from the oven and allow to rest for 2–3 minutes before serving

While the cod is cooking, make the fricassee. Add the butter to a pan and place over a low heat. Once melted, add the shallot and garlic and cook until soft but without colour. Add the chicken stock, bring to the boil then remove from the heat. Add the lettuce and peas, stir well, and allow to sit for 2 minutes. Season with salt and pepper

Crush the potatoes lightly just before serving

To serve, place 2–3 spoonfuls of the potatoes in the middle of each plate make a small well in the centre. Spoon the fricassee of peas into the potatoes, place the cod on top and spoon over the hollandaise sauce