Heat dashi broth in a saucepan over medium heat without bringing it to a full boil.
Add cubed tofu and soaked wakame seaweed, cooking for 2–3 minutes.
In a small bowl, dissolve miso paste with a ladle of warm broth until smooth.
Stir the dissolved miso back into the pot.
Heat gently without boiling to preserve the miso's flavor and nutrients.
Add sliced green onions just before serving.
Serve hot as a side dish or light meal.