Add the dashi to the saucepan. Add the miso (typically, use 1 Tbsp miso for every 1 cup (240 ml) of dashi). Put the miso in a sieve, whisk with dashi to dissolve the miso completely. If you accidentally add too much miso, dilute the miso soup with dashi (or water).

Cut the tofu into ½-inch (1.3 cm) cubes and add to the miso soup. Tip: Add the tofu after the miso is completely dissolved; otherwise, you might break the tofu when stirring in the miso

Add the dried wakame seaweed. Reheat the miso soup until it is just hot. NEVER BOIL miso soup because it loses nutrients, flavor, and aroma. Add the chopped green onions right before serving to keep their fresh fragrance and color. Tip: If you worry about salt intake, I recommend rehydrating the dried wakame in a separate bowl of water to get rid of the saltiness, instead of rehydrating it in the soup itself.

To Store
In general, it's best to consume all the miso soup right away because it will lose its aroma and taste as time passes. Let your miso soup cool to room temperature (up to 4 hours; any longer and it will spoil) and then refrigerate.

Keep for up to 2 days in the refrigerator. If you want to make a big batch to store for later, it's best to refrigerate the soup without adding the miso. When ready to use, add the miso only for the portion you need. You can freeze miso soup for up to 2 week

To Reheat the Miso Soup
Heat the miso soup in a pot over medium heat, but do not boil. Miso loses its nutrients, flavor, and aroma at high temperatures.