Dissolve miso paste in water in a small bowl and whisk to combine.
Add veggie broth, miso paste liquid, and scallions to a soup pot over medium heat.
Once warmed throughout (about 10 mins) add mushrooms. Cook for 5 more minutes.
If you are using silken tofu, add chunks of tofu to the soup and heat on medium for another 5 minutes.
If you are using noodles instead of tofu, I suggest adding the noodles to each serving bowl and adding the broth on top. If you plan on having leftovers I think it's better not to have noodles in the soup broth.
One soup is in serving bowls, add seaweed on top! Serve with a miso soup spoon!