Start by heating the dashi in a pot over medium heat.
Once the dashi is warm, reduce the heat to low.
In a bowl, mix the miso paste with a small amount of warm dashi until smooth.
Add the miso mixture back into the pot, stirring gently to combine.
Add the cubed tofu to the pot and let it warm through for a few minutes.
Add the rehydrated wakame seaweed and sliced green onions.
Optional: Add any additional vegetables you like, such as mushrooms or spinach.
Allow the soup to simmer gently for another 2-3 minutes.
Adjust the seasoning if necessary; you can add more miso for a stronger flavor.
Serve hot, garnished with extra green onions if desired.