In a large stockpot, bring the water or broth to a boil over high heat then add your shiitake mushrooms and reduce heat to medium-low. Simmer for 8-10 minutes for the mushrooms to cook and start to flavor the broth.
Next stir in your kale. Continue to simmer the mixture for an additional 5 minutes, or until the kale starts to wilt.
Carefully scoop out about a half a cup of the warm broth to mix with your miso paste. Stir until the miso is fully incorporated then add back to the pot along with the tofu, radishes, ginger and garlic. Simmer on low for an additional 5 minutes.
Taste and adjust any seasoning to your liking. Scoop into bowls to serve.