Since this is a 'recipe' I got from a friend, and it's not something I could find online, I thought it would be a good idea to write up.

This is a soup that uses red miso (not white or black), mushrooms, tofu, and brown rice. Depending on how much rice and tofu get added, it can be pretty hardy.

Ingredients:
6-8 cups water
2 pieces kombu
2 Tbsp olive oil
~5 big shitake mushrooms
~5 oyster mushrooms
1/2 block tofu
1 cup cooked brown rice
1/4 cup red miso
1/4 cup soy sauce

First, pour the water into a medium-sized pot and drop in the kombu. Turn the heat up to medium. Note: you do not want the kombu to boil. I hear it turns bitter if it does.
In the meanwhile, cube the tofu, and measure out the rice. Then, chop up the mushrooms and saute them in the olive oil until they are cooked.
Once the mushrooms are done, take out the kombu and drop in the mushrooms, tofu, and rice. Let it simmer for a few minutes and in the meanwhile, dissolve the miso in a bit of hot (not boiling) water.
Now, turn off the heat, wait for the soup to stop boiling, and mix in the miso. The final step is adding the soy sauce. My measurements are approximate and you might want to start at 2 Tbsp and keep going until it tastes right to you.

Enjoy!

Let me know of any suggestions in the comments.