Chop the sweet potato and atsuage into bite-sized pieces. Shred the shimeji mushrooms. Slice the leek diagonally.
Add dashi stock, and all the ingredients in a pot, and turn on the heat.
Skim off the scum carefully.
When the sweet potato is cooked through, turn off the heat, and dissolve the miso in the soup.
Heat again without bringing to a boil, and it's done.
Story Behind this Recipe
It got a little bit cool, and it made me crave miso soup that I could enjoy the taste of fall.
The amount of the miso is just a suggestion because the brand and taste varies on the family. If you cook the sweet potato too long, it falls apart, so when it cooked through and become translucent, it's done. You can substitute shimeji mushrooms and Japanese leek with other mushrooms and onions. They will be delicious, too. Sprinkle ichimi pepper. It will also be delicious.