White fungus or white wood ear fungus (白木耳) or snow fungus (雪耳) or silver ear fungus (银耳), whatever you called it is a species of fungus that grows on dead tree. This fungus is white with a gelatinous fruit bodies and said to have medicinal benefits. In Chinese cuisine, we mostly cook it in sweet soup or herbal savory soup. You can even stir-fry with it.
I wanted to make split mung bean soup because it was quick and easy as it cooked really fast without much prior soaking required. Then, I remembered I made a nagaimo mung bean soup before which made me think what else could I used instead of nagaimo that I had at home. Which came out to be white fungus. I thought the crunchy white fungus would go well with my mung bean soup and hence this soup was created. Got to say, it was good! What a great way to trick my girls into eating the white fungus.
Oh, I had lots of broken bits of white fungus in my packet and thus that was what I used for this soup. If your white fungus are in pieces, just take one and soften it in water and then cut it into smaller pieces.