Legend has it that the dish originated during a heavy snowfall when some shepherds had nothing to eat but potatoes and a few bones of cod. They boiled the potatoes with the cod and mashed them, mixing them with the boneless scraps, but seeing it wasn't enough, they started adding olive oil and stirring it with the mortar. The mixture thickened, and they had such a feast that when they finished, they said, "this fills even the donkeys," and hence the name.
It is a traditional dish from the mountains and is usually eaten when the first snows fall. It is even said that for it to turn out really good, melted snow should be used for cooking. The exquisite small walnuts from the mountains are added to garnish and complete a nutritious dish. Like most country dishes, it's better not to use plates and eat directly from the mortar.