This is Aiden's recipe, it'll serve four people:
- 1 litre of milk
- 1 garlic clove, halved
- 4 large sprigs of thyme
- 1kg of cod fillet
- 75ml of fish stock
- 100ml of double cream
- 2kg of watercress
- 1 large potato, peeled and finely sliced
- 25g of butter
- 1.5 litres of boiling vegetable stock
- 4 large eggs
- 75 ml of white wine vinegar
- 2 tablespoons of chopped chives
- Cracked pepper
Before you start have a large bowl of iced water ready with another large bowl sitting on top of the ice so that you can chill the soup immediately to keep its freshness and colour.
Fill your deepest saucepan with water and bring to a high boil.
Heat the milk with the garlic and thyme sprigs, remove from the heat and leave to infuse.
Meanwhile, season the cod with salt and cracked pepper. After 15 minutes return the milk to the heat, put the cod in the milk and allow it to cook slowly for two minutes. Remove from the heat and leave the cod until the milk cools. Remove the fish from the milk and flake it on to a plate. Set aside.
Put the fish stock in a saucepan and heat to reduce by half. Add half the double cream, reduce the liquid again by half and keep warm.
Pick the leaves from the watercress stalks. Sweat the onion and potato together in the butter in a covered, heavy-bottomed pan, making sure that they do not colour. If the potato sticks then add a little vegetable stock and remove the stuck potato with a wooden spoon. Cook until the potato is soft. Add two thirds of the watercress leaves and cook for a further two minutes. Add the hot vegetable stock and return to the boil. Add the rest of the cream and reboil. Transfer the mixture to a blender and blend in batches until smooth. Add the remaining watercress as you blend; this will give a fresher soup, in both flavour and colour. Pass the soup through a fine sieve in the bowl set on iced water then immediately transfer to the refrigerator.
Crack the eggs into the four separate cups and turn down the boiling water to a low simmer. Add the vinegar and drop the eggs in one by one. Cook the eggs for one-and-a-half minutes and plunge them into iced water to stop cooking.
To serve: Gently reheat the soup. Reheat the cod flakes in the fish cream and add the chopped chives. Reheat the poached egg in hot water. Put the soup in four bowls, spoon in the creamed cod and top with a poached egg.