- Cook pasta per package directions, rinse, drain and set aside.
- Place 4 cups water, kombu, and shiitake in a medium saucepan. Cover and bring to a boil. Reduce heat to medium-low and simmer 4 to 5 minutes.
- Remove Kombu, set aside for soup stock or discard. Cover pan and simmer 10 minutes.
- Reduce the heat to low, add shoyu, and simmer 2 minutes.
- Place the cooked soba in serving bowls, ladle the hot broth over, and garnish each with gomasio and scallions.