Put all stock ingredients in a pot over medium high heat. Bring to a boil then reduce heat to a simmer for about 5 minutes.
In a small bowl, add 1/4 cup of the stock in the pot and then add the remaining sauce ingredients. Mix until smooth and then add to the stock pot.
Add rice cakes, carrot, and kimchi to the pot and continue to simmer. After 3-4 minutes add both bok choy and the napa cabbage, cover and simmer another couple of minutes until the greens start to wilt.
Now add the tofu, pickled radish, and tempeh. Cook for another minute or so. Add the noodles and stir well so they don't stick. Continue simmering until the noodles are done, about 4-5 minutes for soba noodles. Quick cooking noodles are best here. If there isn't enough liquid to keep the noodles covered, add a little more water.
While the noodles are cooking, take about 1/4 cup of stock out of the pot and put in a small bowl, the same one you used for sauce earlier is fine. Add a teaspoon of miso paste and mix until smooth. Add back into stew and stir.
Taste for seasoning. Add more red pepper flakes if you want it spicier. If it needs more depth of flavor, add more miso paste mixture or Bragg Liquid Aminos. When the noodles are done it's ready to eat!