Soft tofu and seaweed float in a miso-flavored broth in this Chinese-Japanese fusion soup. This vegetarian, protein-rich family soup is healthy, low calorie, and supports a dash diet plan.
Soak the dried seaweed in cold water for 10 minutes until fully rehydrated, then drain and set aside.
Wipe shiitake mushrooms and thinly slice them; slice scallions on the diagonal and cut tofu into 1-inch cubes.
Bring 5 cups water to a gentle simmer in a medium pot over medium heat.
Add mushrooms and rehydrated seaweed to the pot. Simmer uncovered for 5 minutes to build umami flavor.
Reduce heat to low. Gently add tofu cubes and continue warming for 3–4 minutes—do not allow to boil.
In a small bowl, whisk miso paste with a ladle of hot broth from the pot until smooth. Stir the miso mixture back into the soup. Add soy sauce and sesame oil.
Stir gently and shut off the heat as soon as the miso is fully incorporated (do not let the miso boil).
Ladle soup into bowls, top with sliced scallions and a drizzle of extra sesame oil, if desired. Serve immediately for best texture.