Prepare the Dashi Broth: Start by gently wiping the kombu with a damp cloth to remove any dust, but do not wash off the white powder, as it contains umami. Place the cleaned kombu in a medium saucepan along with 1000ml (4 cups) of cold water. Let the kombu soak in the water for at least 30 minutes to an hour. This rehydrates the kelp and begins to infuse the water with its subtle flavor.

Heat the Dashi: Place the saucepan with the kombu and water over medium-low heat. Slowly bring the water to a gentle simmer. Do NOT let it boil. As soon as small bubbles start to appear around the edges of the pot (around 80-90°C or 175-195°F), remove the kombu from the pot. Boiling kombu can make the broth bitter.

Add Bonito Flakes: Once the kombu is removed, increase the heat slightly to bring the water to a gentle boil. Add the 10g (0.35 oz) of katsuobushi (bonito flakes) to the simmering water. Let it simmer for about 1 minute, then turn off the heat. Allow the bonito flakes to steep and sink to the bottom for about 5-10 minutes.

Strain the Dashi: Carefully strain the dashi broth through a fine-mesh sieve lined with cheesecloth or a paper towel into a clean pot or bowl. Discard the used bonito flakes and kombu. You should have a clear, fragrant broth. This is your base dashi.

Prepare Other Ingredients: While the dashi is steeping, prepare the silken tofu by carefully cutting it into approximately 1.5cm (0.6 inch) cubes. In a separate small bowl, place the 5g (0.17 oz) of dried wakame seaweed and cover it with cool water. Let it rehydrate for about 5-10 minutes until it becomes tender and expands. Drain the rehydrated wakame thoroughly.

Heat the Soup Base: Pour the strained dashi broth back into a clean saucepan. Add the cubed silken tofu to the dashi. Gently heat the broth over medium-low heat until it is warm, but do not let it boil vigorously, as this can break apart the delicate tofu.

Incorporate Miso Paste: Once the tofu is warmed through, reduce the heat to low. In a small bowl or ladle, add 4-6 tablespoons (60-90g) of miso paste. Ladle a small amount of the warm dashi broth (about 1/2 cup or 120ml) into the bowl with the miso paste. Whisk gently until the miso paste is completely dissolved and smooth. This tempering process prevents the miso from clumping and ensures an even flavor.

Combine and Finish: Pour the dissolved miso mixture back into the saucepan with the dashi and tofu. Stir gently to combine. Add the drained rehydrated wakame seaweed to the soup. Heat gently for another 1-2 minutes until the soup is heated through, but again, do not let it boil.

Serve: Ladle the hot miso soup immediately into individual bowls. Garnish each bowl with finely chopped scallions. Serve hot as a traditional accompaniment to Japanese meals.