• 2 lb (900 g) potatoes, scrubbed and roughly sliced
• 5 leeks, thinly sliced
• 12 oz (350 g) tomatoes, skinned and de-seeded
• 3 small celery hearts, quartered
• 3½ pints (2 litres) water
• Sea salt and freshly ground black pepper
• Bouquet garni
• 3 lb (1.4 kg) fish, cleaned and sliced, no bones
• 3 egg yolks
• 4 tablespoons cream
• Croutons

Put the potatoes, leeks, tomatoes and celery into a large pan with the water, seasoning and bouquet garni. Bring to the boil and cook for 25 minutes.

Add the fish and cook gently for another 15 minutes. Remove from the heat. Mix the egg yolks with the cream and stir gently into the soup. On no account allow to boil again. Scatter the croutons over the soup before serving.