Preparation:
Wipe Kombu with a damp paper towel then place in a container. Add 4 cups water, cover and refrigerate overnight. Remove and discard kombu.
Bring kombu stock to a boil in a medium pot over medium-high heat. Add bonito flakes, cook for 10 seconds then remove pot from heat. Let stand for 2 minutes then strain dashi (stock) through a sieve lined with cheesecloth. Discard bonito flakes. If you are not using dashi immediately it may be stored in a covered container in refrigerator for 1 week or in freezer for up to 1 month.
Put wakame in a bowl, cover with cold water, and soak until soft, about 10 minutes. Rinse well to remove salt. Cut away any hard ribs then slice wakame into 1" pieces.
Pour dashi in a medium saucepan and bring just to a boil over medium-hig heat. Whisk in akamiso and shiromiso until they dissolve then reduce heat to low. Do not allow soup to return to a boil. Add tofu and simmer for about 1 minute. Just before serving divide wakame and scallions between 4 soup bowls then fill each bowl with hot soup. |