Black truffle of the Sobrarbe Food and drink · Aínsa-Sobrarbe, Sobrarbe, Huesca The fungus is gathered in winter with a dog in the comarca's holm-oak scrub and celebrated every first weekend of February with a fair in the castle's parade ground, with a searching competition and fresh truffle tapas. Photo: Diego Delso (CC BY-SA 3.0) What to see and do in Aínsa-Sobrarbe