Saffron milk caps and usones from the Serrablo forests Food and drink · Yésero, Alto Gállego, Huesca Image of Yésero, not of the place itself. The pine woods and the pastures of the sierra give saffron milk caps in autumn and usones in spring, the two most gathered mushrooms of the comarca; they are stewed with garlic and ham or added to the migas and to the lamb roasts. Photo: Willtron (CC BY-SA 3.0) What to see and do in Yésero