Bring the vegetable broth to a boil and add the dried mushrooms and seaweed.
(Add the dried mushrooms now, let them soften, and remove them and slice before adding back to the pan with the other ingredients.)
Simmer until mushrooms are softened, about 10 minutes.
Add the fresh mushrooms and tofu and simmer until the mushrooms are tender.
Ladle out about 1/2 cup of the broth and stir it into 2 tablespoons of the miso. Mix until smooth and add to the pot.
Taste, and if more miso is needed, repeat the process with another tablespoon of miso.
Allow the soup to simmer for about 5 more minutes without boiling and serve.