Spoon the miso into a small mixing bowl and add about one cup of the soup broth. Whisk until smooth, then mix into the soup. Add the baby bok choy. Taste the soup, and add salt to taste. Serve garnished with scallions, sprouts, or extra enoki mushrooms.
To save from chopping the reconstituted mushrooms later, crumble them into the hot water. For thick pieces, use kitchen shears to cut them into small pieces.