Bring a large pot of water to a boil over medium heat.
Add wakame and nori seaweed (if using), shimeji or shiitake mushrooms, spinach, scallions and tofu.
Cook for about 5 to 7 minutes.
Meanwhile, whisk miso paste with about 1 cup of hot (not boiling!) water until smooth to prevent lumps.
Add to the soup and turn off the stove. Enjoy!
