Recipe for miso broth only (no extra ingredients)?

I’m trying to make miso broth for the first time. I bought white mellow unpastuerized miso. I tried looking up recipes, but I keep seeing the cooking times for all these other ingredients in it, and I don’t know how long I need to cook it if I’m only using the miso paste and water. Is there a recipe for that?

You can’t. Miso broth is never ever made with just miso. It always uses dashi (shaved/powdered/liquid from fish), and almost always has either tofu and/or negi (green onions). If you’re vegetarian, you’ll still need some for of flavoring to replace the dashi, because miso itself does not have enough flavor for the soup to be pleasant. I’m not sure what to suggest though–in Japan, some for of fish stock and/or flavoring is basically always used.