Add dashi stock to a pot and heat over medium heat. When it boils, use your hands to crumble the tofu into the pot.
Dissolve the miso in some of the stock as you add to the pot. Add natto and ginger. Turn off the heat just before it starts to boil. Transfer to serving bowls and scatter the julienned shiso leaves on top of the soup.
Story Behind this Recipe
My husband doesn't like the smell of natto soup. When I added shiso leaves and ginger, he was able to eat it and now it's become one of his favorite dishes.
This soup is delicious piping hot, but just be cafeful not to make it too hot! Use any kind of natto you like. Hikiwari natto will make the soup really thick and creamy.