01 - Preheat oven to 400°F. Place garlic cloves on foil, drizzle with 1 tsp olive oil, wrap, and roast for 15 minutes until soft and golden.
02 - Heat remaining olive oil and butter in a large pot over medium heat. Add onion, carrot, and celery; sauté for 5 minutes until softened.
03 - Add mushrooms, thyme, and rosemary to the pot. Cook, stirring occasionally, until mushrooms release moisture and brown, about 8 minutes.
04 - Squeeze roasted garlic from skins into the pot and stir to combine.
05 - Pour in vegetable broth and bring to a boil. Reduce heat and simmer uncovered for 15 minutes.
06 - Use an immersion blender or transfer in batches to a blender to purée the soup until smooth and creamy.
07 - Stir in heavy cream, season with salt and black pepper to taste, and heat through for 2 to 3 minutes.
08 - Ladle into bowls, garnish with chopped parsley and a swirl of cream if desired. Serve hot.