Location and Uses
Hyrule Compendium Entry
Rushrooms are purple Mushrooms that can be commonly found growing on mountains and cliffs, mainly in the Gerudo Highlands and the Hyrule Ridge. When a singular Rushroom is Cooked in a Cooking Pot, it will produce a Hasty Mushroom Skewer that, when eaten by Link, will provide a speed boost for one minute and heal Link of one Heart.
A mushroom that can grow almost anywhere but prefers ceilings and sheer cliffs. Cook it before eating to temporarily increase your movement speed." — Inventory (Breath of the Wild)