In a large pot, make about 4 cups of dashi. I use my 4 cups of water and steep one dashi packet for 3-5 minutes, like I'm making tea. Of course, you can make dashi from scratch as well, if you'd like.
Bring dashi to a boil. Add garlic, onions, and potatoes.
Simmer for 5-10 minutes, or until the cubed potatoes are soft. The smaller you cut the potatoes, the quicker they'll cook. Once they're soft, add in your zucchini, mushroom, and tofu. These only take 1-2 minutes to cook.
Turn off the heat and dissolve in your miso to taste. I usually start with about 1 tbsp per cup of water, but you can start with less and keep adding until it's flavorful enough for you. Also stir in your gochujang or other chili sauce, if using.
Serve by itself, with noodles, or over rice!