Heat 4 tablespoons of olive oil in a large pot over medium heat. Add 1 pound of diced mushrooms, 8 minced garlic cloves, ½ teaspoon salt, and 2 diced medium onions. Cook for 5-7 minutes, or until the onions are softened.

Add 1 pound of sliced mushrooms, stir to coat in oil, and cook for 10-12 minutes, or until the mushrooms release their liquid and start to brown.

Add 1 sprig of fresh rosemary, 3 teaspoons of dried thyme, ½ teaspoon salt, and ¼ teaspoon black pepper. Stir and cook for 1-2 minutes, until fragrant.

In a small saucepan, bring 2 cups (475 ml) of water and 1 bouillon cube to a boil. Remove from heat and mix until the bouillon cube is fully dissolved. Transfer to a blender, add 2 cans of cannellini beans, and blend until smooth to create the "cream of bean" mixture.

Add 1 tablespoon of balsamic vinegar and the cream of bean mixture to the pot with the mushrooms. Gently stir until fully combined. Add 6 cups of broth or stock and bring the soup to a gentle simmer. Cook for 10-15 minutes, stirring occasionally.

Taste the soup and add additional salt, up to ½ teaspoon, if necessary. (Depending on the sodium content of your broth or stock, you may need to adjust the seasoning. If you add more salt, allow the soup to simmer for an additional 5 minutes before serving.)

Remove the rosemary sprig and serve the soup hot, garnished with chopped fresh oregano or parsley, alongside crusty bread.