Soak the dried mushrooms in the warm water for 30 minutes. Remove and chop finely. Strain the water through kitchen towelling and reserve. Wipe the fresh mushrooms with a damp cloth, or, if they are too dirty, rinse quickly in cold water and dry well. Slice lengthways without detaching the stalks.
Heat the butter and oil in a heavy frying pan and sauté the garlic and parsley until soft