Dashi and Miso Soup (Miso Shiru)

Gently wipe the kombu with a damp cloth to remove any grit, but do not wash off the white powder, as it contains umami. If using dried shiitake, rehydrate them in warm water for about 20 minutes.

Add the water and kombu to a pot. Bring to a gentle simmer over medium heat. Do not boil. Remove the kombu just before the water boils, about 5-10 minutes.

Add the bonito flakes and rehydrated shiitake mushrooms (if using) to the pot. Bring back to a simmer, then immediately reduce heat to low and let it steep for 5 minutes. Do not boil.

Strain the dashi through a fine-mesh sieve lined with cheesecloth into a clean bowl or pot. Discard the solids. You should have about 1.5 liters of dashi.

Pour the strained dashi into a clean pot and bring it to a gentle simmer over medium heat.

In a small bowl, whisk the miso paste with a ladleful of the warm dashi until smooth. This prevents clumps.

Add the silken tofu cubes to the simmering dashi and heat through for about 2-3 minutes. Do not boil vigorously.

Stir the dissolved miso mixture into the pot. Heat gently for another minute, but do not let the soup boil after adding the miso, as this can diminish its flavor and aroma.

Ladle the miso soup into bowls. Garnish with thinly sliced scallions.