Make the dashi: If using instant dashi, dissolve the granules in hot water according to the package for 4 cups of broth. If making from scratch, gently simmer a piece of kombu (about 4-inch/10 cm) in water, remove before boiling, and finish with bonito flakes (see FAQ for details).

Warm the broth: Place the dashi in a medium pot over medium heat. Keep it hot but below a full boil. A gentle steam is perfect.

Prepare the tofu and wakame: Cut tofu into bite-size cubes. Soak dried wakame in cool water for a few minutes until it expands, then drain and chop if pieces are large.

Add wakame (and mushrooms, if using): Stir them into the hot dashi and let them soften for 1–2 minutes.

Temper the miso: In a small bowl, ladle in a scoop of hot dashi. Whisk in 3 tablespoons miso until smooth. This prevents clumps and protects miso’s delicate flavor.

Stir in miso and tofu: Lower the heat. Add the miso mixture to the pot and gently slip in the tofu. Do not let the soup boil after adding miso—keep it just below a simmer.

Taste and adjust: If you want more depth, add a little more miso or a teaspoon of soy sauce. Aim for a balanced, savory broth that isn’t too salty.

Finish with scallions: Turn off the heat. Stir in the sliced scallions just before serving for fresh aroma and color.

Serve immediately: Ladle into bowls and enjoy while warm. Miso soup is best fresh.