dried shiitake
Dried shiitake mushrooms, soaked before cooking, with a deep, smoky, savoury flavour and a firm, meaty texture.
Caution: Shiitake should be eaten thoroughly cooked, as raw or undercooked mushrooms can trigger an itchy, streak-like skin rash in some people.
Dried shiitake are reliably found in Asian grocers and by mail order, and smaller packs often turn up in well-stocked supermarkets or health food shops; thick caps with a cracked surface are considered the best. They are soaked in cold water for several hours or overnight, and the soaking liquid makes a savoury stock for broths and sauces.
Substitute:
Fresh shiitake match the texture but have far less depth and give no soaking liquid; dried porcini deliver a similar savoury intensity but taste earthier and not like shiitake.