Instructions

1. Place 2 cups water and 1 (2x2-inch) piece dried kombu in a small saucepan. Place over medium heat (do not go hotter; you want the water to heat up slowly). Right before the bubbles start to release from the bottom of the saucepan, turn off the heat.
2. Remove the kombu and reserve for another use or discard. Add 1 cup loosely packed katsuobushi to the saucepan. Return the broth to a simmer and cook for 1 minute. Turn off the heat and let the katsuobushi steep while you prepare the remaining ingredients.
3. Place 2 teaspoons dried wakame in a small bowl if using. Add enough cold water to cover. Thinly slice 1 to 2 scallions until you have about 2 tablespoons. Cut 4 ounces soft tofu into 1/2-inch cubes (about 1/2 cup).
4. Pour the broth and katsuobushi through a fine-mesh strainer set over a liquid measuring cup or medium bowl (this is dashi). Reserve the katsuobushi for another use or discard. Rinse the strainer.
5. Return the dashi to the saucepan and bring back to a simmer over medium heat. Turn off the heat. Place 2 tablespoons white or red miso paste in the strainer and press through the strainer into the broth with a whisk or chopsticks. Discard any remaining chunks in the strainer.
6. Strain the wakame. Add the wakame, scallions, and tofu to the soup.