- In a pot, bring the water to a gentle simmer. 
- Add the dried seaweed and let it rehydrate for about 5 minutes. 
- Reduce the heat and add the tofu cubes. Let them warm through. 
- In a small bowl, mix the miso paste with a bit of hot broth until smooth. 
- Stir the miso mixture and soy sauce into the soup. 
- Turn off the heat and add green onions just before serving.