Black ear mushrooms mature in sixty days and can be eaten once blanched, but this is not recommended as one mistake could kill your character. Blanched mushrooms are obtained by using the "Boil / Herbal beverages" cookery option. Applying Herblore skill on a container of boiled black ear mushroom reports it as being "edible", and boiled black ear mushrooms can be used as ingredient in other cooking recipes such as mushroom soup. Merely cooking raw black ear mushroom in a mushroom soup does not count as boiling and does not neutralise the Deadly poison.