Cook noodles according to package directions. Drain and set aside.

Heat the water in a pot and when it starts to boil, add the dried wakame seaweed and cook over medium heat for about 5 minutes.

Add the miso paste into a small bowl, add some hot water and whisk until smooth. Add to the soup after removing the pot from the heat and stir.

Add the tofu and the green onion and stir again. You can cook the tofu and the green onion if you want for 5 minutes, although it's not necessary. Don't cook the miso paste.