1. Sprinkle the sea salt, a sprig of thyme and two garlic cloves over the cod. Cover with cling film and keep refrigerated for 12 hours.
2. To make the stock, gently heat the shallot in the oil and a tsp of butter for two minutes. Add the carrot, leek and a garlic clove and heat for five minutes. Add the scallop trimmings, wine, bay leaf and a sprig of thyme and boil for five minutes. Strain everything and keep the liquid, discard everything else.
3. For the sauce Ecossaise, separate the boiled egg yolks from the whites. Put the yolks to one side and finely slice the whites.
4. Melt a teaspoon of butter. Add the flour and whisk for two minutes. Add the milk and keep stirring until it starts to boil.
5. Add the scallop stock and simmer for five minutes. Season with cayenne, nutmeg, pepper and salt.
6. Place the cod on a buttered tray and cover with foil. Cook in the oven at 180C/Gas Mark 4 for seven minutes.
7. Flake the cooled cod into the sauce. Add the yolks. Give it a firm stir. Add the whites and season.
8. Sear the scallops in a hot pan with oil and a teaspoon of butter for two minutes per side.
9. To serve, fill the scallop shells with warm sauce Ecossaise and top with the cooked scallops and the parsley.