Cut tofu, zucchini, onion, and shiitake mushrooms into bite-sized pieces.
Pour 400ml of water into a pot and add kelp to make broth.
Add 30g of doenjang (soybean paste) to the broth and dissolve.
Add zucchini, onion, and shiitake mushrooms to the pot and bring to a boil.
Once the vegetables are cooked, add tofu and minced garlic.
Season with chili powder and soy sauce to taste.
When boiling, top with green onion to finish.