What Are Porcini Mushrooms? Porcini mushrooms Porcini mushrooms are brown-capped mushrooms with thick, white stalks. The caps can range in size from an inch to nearly a foot, but most collected specimens are no more than a few inches. The caps have a convex shape when young, giving them the ideal appearance for mushrooms, and require no prep other than a quick clean. Because of their status in fine cuisine, their short season, and how difficult they are to cultivate, porcini mushrooms can be pricey. A pound of fresh porcini costs between $30-$60 depending on the quality, with dried mushrooms priced a little lower. Porcini mushrooms, sold both fresh and dried, are prized in Italian and French cuisine. These popular mushrooms (also known as king bolete or  cèpe  in French) are cultivated in Europe, North America, and parts of Asia, and grow naturally in pine forests at the base of trees. Autumn is porcini season in central Europe, with much of the carefully picked