Though originally from Japan and Korea, the delicious shiitake mushroom is now being cultivated in the United States (where it's often called golden oak) in a number of states including California, Pennsylvania, Vermont, Washington and Virginia. The cap of the shiitake is dark brown, sometimes with tan striations, and can be as large as 8 to 10 inches across. The average size, however, is three to six inches in diameter. The meaty flesh has a full-bodied (some say steaklike), bosky flavor. Shiitake stems are extremely tough and are therefore usually removed. Don't throw them out, however they add wonderful flavor to stocks and sauces. Discard the stems after they've been used for flavoring. Though both fresh and dried shiitakes are now available almost year-round in many supermarkets, they're very expensive. Spring and autumn are the seasons when fresh shiitakes are most plentiful. Choose plump mushrooms with edges that curl under. Avoid any with broken or shriveled caps. The versatile shiitake is suitable for almost any cooking method including sautéing, broiling and baking. Shiitake mushrooms are also called Chinese black mushrooms and forest mushrooms.