How to make
Put the lamb heads and entrails to cook in a pressure cooker for about 45 minutes (depending on the age of the lambs). Strain the broth through a fine strainer in another large pot. Debone the heads and cut up the tongue, brain, meat and offal.
Put them with the strained broth on the stove on medium heat. If necessary, top up with more hot water. Once boiled, add the finely chopped onions and chili peppers. Fry the flour in the hot butter until golden brown, dilute it with a little broth and pour it into the soup.
Add salt and black pepper to taste and keep boiling the soup until ready. Remove the dish from the heat and thicken with the yolk or a whole egg and yoghurt. Mix with the finely chopped spearmint, lovage and parsley and serve.