Fairy ring mushrooms (Marasmius oreades) pop up in circles that may grow as large as 33 feet in diameter. Not surprisingly, these little mushrooms have given rise to all sorts of folklore, but one thing is beyond dispute: their big flavor. Even a small amount will transform your soups or stews. Because they have a slightly sweet flavor, they are sometimes used in baked goods. But if you're trying them for a first time, the simplest preparation may be best: once rehydrated, sauté them in butter with onions. To use: Soak the mushrooms in warm water for 15 minutes, drain, then plunge them in boiling water for 10 minutes. Drain and rinse well in running water. Cut off the stalks if you wish. Blot the mushrooms dry, then put them in a pan over high heat to evaporate the remaining water. The mushrooms are now ready to use as desired or directed in your recipe. 100g of dried mushrooms makes 350g once rehydrated.