Heat butter in a large pot over medium-high heat. Sauté onion for 2 to 3 minutes until softened. Sprinkle a little salt and pepper and stir, then add in garlic and cook garlic until fragrant, for about 1 minute.
Add mushrooms and half of thyme, cook for 5 minutes. Pour in wine and allow to cook for 3 minutes.
Add stock, mix again and bring to a boil. Reduce heat to low-medium heat, season with salt, pepper, and garlic granules.
Allow to simmer for 15 minutes, while occasionally stirring, until thickened.
Blend the soup in a blender or using an immersion blender. For a chunkier soup, blend ½ of the mushroom broth mixture until smooth and add it back into the pot, leaving 1/2 of the mushrooms still in the soup. For a silky smooth soup blend all of the mushroom broth mixture in a blender until smooth. It’s completely up to you!
Reduce heat to low, stir in cashew cream or heavy cream. Allow to simmer but do not let it come to a boil. Adjust salt, pepper, and red pepper flakes to taste.
Mix in parsley and remaining thyme. Serve warm garnished with additional parsley and red pepper flakes.