Dried shiitake mushrooms soak in water then use like fresh mushrooms shiitake mushrooms are a great store cupboard ingredient and are great for adding flavour to dishes once soaked these mushrooms reconstitute to 5 or 6 times their dry weight to use soak for 20 minutes in warm water or milk to rehydrate drain and then use like ordinary mushrooms in risottos stroganoffs stews or stir fries dried shiitake mushrooms soak in water then use like fresh mushrooms shiitake mushrooms are