Make the vegetarian dashi: Add 4 cups of water to a pot with the kombu and dried shiitakes. Let them soak for 15 to 20 minutes to soften and release flavor.

Warm gently: Place the pot over medium heat and slowly bring it close to a simmer. Just before it boils, remove the kombu. Simmer the mushrooms for 5 more minutes, then remove them. Strain if needed.

Prep add-ins: Soak the wakame in a small bowl of water for 5 minutes, then drain. Slice the scallions and cut the tofu into small cubes.

Season the broth: Add the wakame to the pot. Taste the broth; if you’d like more depth, add 1 teaspoon soy sauce or tamari. Keep the heat low—no boiling from here on.

Whisk in miso: Ladle some hot broth into a small bowl, add the miso, and whisk until smooth. Pour it back into the pot. Aim for 2 tablespoons first, then taste and add more if needed.

Add tofu and warm through: Gently slide in the tofu and heat for 1 to 2 minutes. Avoid boiling; high heat can dull the miso’s flavor and split the tofu.

Finish and serve: Stir in the scallions. Taste and adjust with a touch more miso or soy sauce. Ladle into bowls and serve hot.