If using water, heat water before adding boullion. Bring water/ boullion or broth to slow simmer, add miso, and whisk to combine. Peel ginger and mince. Peel tough outer leaves off lemongrass, cut into one inch lengths, and then slice into thin strips. Add both to the broth, cover, and let simmer for at least 30 minutes. About 10 minutes before serving, cube tofu (you pick the size) and add to the soup. Slice the green onions on the diagonal very thinly, and sprinkle on just before serving. This soup a great easy, elegant dish. Even my four year old loves it!