1,1 LBS mixed fish fillets (e.g. salmon, trout, sea bass) 1 large onion, chopped 1 carrot, chopped 1 root celery, chopped 1 bay leaf 4-5 black peppercorns 1/2 teaspoon of salt 4 cups water 1 tablespoon of butter 1 tablespoon of flour 1 cup (250 ml) fish stock (or vegetable stock) 1/4 cup (60 ml) milk Salt and pepper, to taste optional parsley, chopped Clean the fish fillets and place in a heatproof saucepan. Add onion, carrot, celery, bay leaf, black peppercorns and salt. Pour the water into the pot and let it simmer over medium heat. When it starts to boil, reduce the heat and simmer gently for 15-20 minutes until the fish is well cooked. Take the cooked fish with the help of a strainer, put it in a bowl and leave it to cool. Melt the butter in another saucepan. Add the flour and fry for 1-2 minutes on low heat, stirring constantly. Slowly add the fish stock or vegetable broth to the pot and stir quickly so that the flour does not clump. Cook for 10 minutes on low heat at medium heat