To a small bowl, add shiitake mushrooms and enough hot water to completely cover them. Allow to sit for at least 10 minutes or until softened. Remove from the water, reserving the soaking liquid. Squeeze out excess moisture from the shiitake, discard the stems, and chop the caps finely.
In a small bowl, combine the miso, soy sauce, and about 4 tablespoons of the shiitake soaking liquid to make a smooth paste.
In a large frying pan, briefly saute the chopped shiitake, green onion, and ginger int he sesame oil over high heat. Lower the heat to medium. Add the tofu to the pan, crumbling it with your hands. Add the salt. Keep stirring the tofu, using two pairs of cooking chopsticks held together (or just keep breaking apart with wooden spoon), until it starts to resemble fine, rather dry scrambled eggs.
Add the miso sauce to the pan and continue stirring until the liquid is completely absorbed and the pan is dry. Season with black pepper to taste.
Let cool completely before packing or using. This dish is best made the night before. It can be stored in the refrigerator for up to a week. It does get a little tough if it’s been frozen, though it’s still pretty good.