Mince a clove of garlic and dice 1/2 a small onion as finely as possible. Meanwhile, heat a tablespoon of olive oil in a saucepan.
Fry the garlic in the saucepan along with the bay leaf. Be careful not to burn the garlic. Use more oil if you think it's necessary.
When the garlic starts to brown, throw in the diced onion. Saute them until they turn translucent. Add some water if the bottom of your saucepan turns sticky and/or brown to prevent anything from burning.
While saute-ing the onions, you can dice or slice the mushrooms to whatever size you want. I dice most of them and slice one or two mushrooms for some variety.
Throw the mushrooms in the saucepan and let it sweat in there for a minute or two. Add in 1/2 teaspoon of balsamic vinegar.
Add in 3 cups of water and 1 teaspoon of vegetable bouillon paste (I use better than bouillon). You can use 1 stock cube if you don't have bouillon paste.
Cover the saucepan and let it boil. When it starts boiling, reduce flame and allow it to simmer for about 10-15 minutes.
Scoop out a few tablespoons of the soup/liquid and mix it with 1 tablespoon of cornstarch in a separate bowl. Make sure there are no lumps and then pour back the mixture into the saucepan. Cook for another minute or two. You can add more cornstarch if you'd like a thicker soup. If you don't have cornstarch, you can skip this step.
Turn off the heat and add in 1/2 cup coconut milk. Stir well. Don't let the coconut milk boil violently or else it will separate. To reheat on the stove just bring it to a light boil (like a simmer).
Add salt and pepper to taste. Done!