All dried mushrooms must be soaked before cooking, but even so the stems tend to stay determinedly tough unless you simmer them for a prolonged period in liquid, as in, for example, a stew. They are best used in stocks.
Soak all dried wild mushrooms for 20–30 minutes in warm water or stock, then put them through a muslin-lined sieve, keeping the soaking liquid to add to stock or a stew. Rinse the reconstituted mushrooms thoroughly in a colander, then cut off the tough ends of the stems, using these in a stock. Cut the remaining flesh into strips before cooking.