In a large pot, heat the olive oil over medium heat. Add the chopped onions and sauté until translucent, about 5 minutes.

Add the minced garlic and sliced mushrooms, cooking until the mushrooms are softened and browned, about 10 minutes.

Stir in the vegetable broth and soy sauce, bringing to a simmer. Cook for an additional 10 minutes.

Remove the pot from heat and let it cool slightly. Using a blender, puree the soup until smooth. You may need to do this in batches.

Return the pureed soup to the pot and stir in the heavy cream, thyme, and parsley. Season with salt and black pepper to taste.

Heat the soup gently over low heat until warmed through, about 5 minutes. Serve hot.