Creamy Fish Soup

Place 6 cups of water in a pot and add one whole peeled onion, bay leaf, salt, and whole black peppercorns. Bring to a boil. Add the fish to the boiling water and cook for 10 minutes. Transfer the fish to a bowl and leave to cool. Drain the cooking liquid and put it aside. In the same pot, melt the butter and sauté the flour. Add about 1 cup of the reserved cooking liquid and continue stirring. Once the mixture reaches a thick slurry consistency, add the remaining cooking liquid and bring to a boil. Remove the skin and bones from the fish, flake the flesh into small pieces, and add to the pot. Add the cream, stir well, and remove from the heat. Serve hot.