Cut the coarse green tops off the scallions or baby leeks and slice them finely on a diagonal. Put the coarse green tops in a large pan with the cilantro stalks, fresh ginger root, star anise, dried chile and dashi or vegetable stock.
Gently heat the mixture until boiling, then lower heat and simmer for 10 minutes. Strain, return to pan and reheat until simmering. Add the green portion from the sliced scallions or leeks to the soup with the bok choy or greens and tofu. Cook for 2 minutes.
Mix 3 tablespoons of the miso with some of the hot soup in a bowl, then stir it into the soup. Taste the soup and add more miso with soy sauce to taste.
Coarsley chop the cilantro leaves and stir most of them into the soup with the white part of the scallions or leeks. Cook for one minute.
Serve in warmed bowls and sprinkle remaining cilantro and the fresh red chile (optional).