How to cook
Cut the fish fillet into pieces and season it with lemon juice and salt. Leave it to sit like that for 1 hour.
Finely chop the onion and steam it in the oil. Then add 4 cups of water, the fish, black pepper and bay leaf.
Bring the mixture to a boil and boil it for 15 minutes. Remove it from the heat and thicken it with the yolks and yogurt. Cut the bread into small chunks, bake them and drizzle them with melted fresh butter.
Divide the croutons into bowls, pour the soup over them and sprinkle it with parsley.