Prepare the Broth: In a medium-sized pot, heat the dashi broth over medium heat. Once it begins to simmer, reduce the heat to low to keep it warm.
Mix the Miso Paste: In a small bowl, add the miso paste. Take a ladle of the warm dashi broth and whisk it into the miso paste until smooth and dissolved. This step ensures the miso paste dissolves evenly into the broth without clumps.
Combine the Miso Paste with Broth: Slowly pour the miso mixture back into the simmering broth, stirring gently to incorporate. Taste the broth and adjust the miso to your liking, adding more if you prefer a stronger flavor.
Add the Tofu: Gently add the tofu cubes into the soup, allowing them to heat through (about 3–4 minutes).
Add Seaweed and Soy Sauce: Stir in the rehydrated wakame seaweed and soy sauce (if using). Let the soup simmer for another 2–3 minutes to allow all the flavors to meld.
Final Touches: Turn off the heat and ladle the soup into bowls. Garnish with freshly chopped green onions. Serve immediately and enjoy the depth of flavors.
