Rinse fish fillet under cold running water and dry. For the fish, fill a roaster or fish kettle 10 cm high with water. Add salt, peeled onion, vinegar and peppercorns and bring to the boil. Reduce the temperature, put in the fish fillet and let it simmer at low temperature for about 5 to 7 minutes. Skim off the foam as it forms. Remove the fish, drain and keep warm. Reserve 1/2 cup of the fish stock. For the egg sauce, peel and chop eggs. Peel and chop tomatoes and remove seeds. Melt butter in a saucepan. Mix in the fish stock with the eggs, tomato, parsley and chives. Season the sauce with pepper and salt and heat through. Scrape the carrots, cut into slices, drizzle with the juice of one lemon and arrange on the cod. Offer the sauce separately. Serve with long grain rice or boiled potatoes.
(tested circa 1985)