Maitake mushrooms
A Japanese cultivated mushroom that grows in dense, ruffled clusters, with a firm, slightly fibrous bite and a deep, savoury aroma.
Maitake, also called hen of the woods, is a mushroom that grows as a large cluster of many fan-shaped, greyish-brown caps. Rather than being sliced, it is pulled apart into small clusters by hand. Its flavour is earthy and savoury, much stronger than that of button mushrooms, with a faintly peppery edge. When seared in a hot pan the thin edges turn crisp while the base stays firm and juicy, and this contrast is what makes it so useful in stir-fries, tempura and soups. Fresh or frozen maitake can be found in Asian grocery shops, sometimes in well-stocked supermarkets and at market stalls selling cultivated mushrooms, and dried by mail order.
Substitute:
Oyster mushrooms come closest in texture and in how they behave in the pan, crisping at the edges in the same way, but they taste milder; adding a few shiitake partly makes up for the missing depth of flavour.