Heat a large pot over medium-high heat and spray with the coconut oil spray.
Add the sliced mushrooms to the pot and sauté for 5-7 minutes, until softened.
Add the minced garlic and onion to the pot and continue sautéing for 3-4 minutes.
Season with salt, pepper, and thyme. Stir in the beef broth and bring to a simmer.
Cover and simmer for 10 minutes.
Remove from heat, stir in the half and half and blend with an immersion blender until smooth and creamy. (Alternatively, carefully transfer the soup to a blender and blend until smooth).
Ladle into bowls, garnish with fresh parsley, and serve.