- 1/2 cup dried wakame seaweed (available at gourmet and specialty food shops)
- 4 cups dashi
- 1 cup buna shimeji mushrooms, bottoms trimmed (a Japanese mushroom known for its sweetly nutty flavor, it’s available in gourmet and specialty shops)
- 1/4 cup (or more, according to taste) red miso
- 1/2 14-ounce container soft tofu, drained, cut into small dice
- 2 to 3 scallions or Japanese scallions, thinly sliced on the bias
Place the wakame in a large saucepan and cover with water. Cook over medium-high heat just until the water is very hot but not simmering. Remove the saucepan from the heat and let the wakame steep until it softens and expands, about 15 minutes.
Drain the soaking liquid and thinly slice the wakame. Set the wakame aside.
Bring the dashi to a simmer in a large saucepan over medium-high heat. Add the wakame and mushrooms and cook until the mushrooms are cooked through and softened, about 5 minutes. Submerge the sieve into the dashi. Using a wooden spoon, stir 1/4 cup of the miso through the sieve and into the soup. Stir well and taste the soup; if the soup is not salty enough add more miso.
Add the tofu and scallions and cook just until the tofu is heated through and the soup is steaming but not simmering, about 1 minute. Ladle the soup into bowls and serve. To enjoy the soup, sip it from the bowl (traditionally, this soup is not served with a spoon).