1. Separate the hollow green leaves from the solid part of the onion. Finely chop the solid part for use in the soup; then cut up a few of the hollow green leaves to set aside for optional garnish.
2. Heat vegetable oil in a heavy-bottomed pan. Add natto and sauté over low heat, stirring lightly to prevent burning. Add the chopped onion and sauté until soft.
3. Stir in pre-packaged Japanese mustard from the natto along with the mustard.
4. Add the bouillon to the sautéed natto. Wrap thyme and bay leaf together in cheesecloth or pack into a bundle, and add to the pot. Bring to a boil; lower heat and simmer for 2-3 minutes.
5. Add the diced tofu; after it rises to the surface, add the soy milk and 1 t soy sauce, then heat to just under the boiling point.
6. Taste and depending on preference, add another 1/2 t soy sauce or more and sprinkle with black pepper.
7. Serve in individual bowls garnished with chopped green onion leaves, parsley and/or abura-age, depending on preference. Serve hot.

* Either meat- or vegetable-based bouillon cubes or powder may be used. Use about 3/4 the amount of bouillon suggested in directions for a mild soup base.
** Preheat a non-stick frying pan. Over low heat, lightly brown both sides of the abura-age, pressing it down. Remove pan from heat, brush tofu with soy sauce. Cut in half and slice into 5 mm (1/4 in.) strips.

Recipe by Michiko Yamamoto

1 C (U.S. cup) = approx. 240 ml; 1 T = 15 ml; 1 t = 5 ml