Peel the satoimo and cut into bite-sized pieces. Sprinkle with a little salt to remove the sliminess, then rinse with water. Trim the root ends of the shimeji mushrooms and separate them into smaller clusters.

In a pot, add the satoimo, water, and dashi powder. Bring to a boil over medium heat and cook for about 5 minutes until the satoimo becomes tender.

Add the shimeji mushrooms and cook for another 2 minutes. Then dissolve the miso paste into the soup.