|The hard shelled black truffles (melanosporum, aestivum and the Chinese black truffle) do retain some measure of flavor when dried, though not nearly as much as they retain when crocked in butter or frozen under a protective coating of fat. None of the soft truffles can be dried with any success in my experience, but if you do want to try this method on truffles, you could use any of the hard shelled black specimens with at least some chance of a fair result. Use dried black truffles in recipes requiring long, slow cooking, such as sauces and soups, or rehydrate them overnight in the refrigerator in a small amount of savory liquid such as broth or wine.
To dry mushrooms and preserve as much of their flavor as possible, slice them fairly thickly (1/4–1/5") and lay slices on a cookie sheet in the oven. Leave on very low heat (150–200°F) for several hours or until mushrooms are dry to the touch but not brittle.
Keep all dried mushroom products in the freezer or refrigerator to prevent unwanted insects from contaminating the product. The moth that seems to particularly like dried mushrooms has been known to defeat "airtight" containers, and cold storage seems to be the only reliable way to keep your valuable dried mushroom collection from becoming a bug hatchery.
If your dried mushrooms collection does sprout bugs and it is too expensive to throw away, don't panic. Microwave them several minutes on medium power to kill insects and eggs, and wash thoroughly in water. Scatter them on a cookie sheet and bake them dry, leaving them at about 225° for 30 minutes to an hour (keep checking them for burning or brittleness) until they are completely dry again. Allow to cool, then freeze or refrigerate in Ziploc bags. Mushroom bugs are harmless, but not tasty, and this proceedure will remove them from your culinary collection.