Place the wakame and water into a pot, cover, and bring to a boil.
Add onions and carrots, cover, reduce flame to medium low, and simmer for 5 minutes.
Reduce flame to low Dilute miso in 1/4 c of the hot broth and add to the soup.
Add bok choy, tofu and mushrooms and let simmer without boiling for 2 minutes.
Serve garnished with scallions.
6 servings