Start by cleaning and slicing your mushrooms. Mince the garlic and chop the onion. Having everything prepped and ready will make the cooking process smoother.

In a large pot, melt the butter over medium heat. Add the chopped onions and garlic. Sauté for about 3-4 minutes until the onions are translucent and fragrant.

Add the mushrooms to the pot and cook for 5-7 minutes, stirring occasionally. You'll notice the mushrooms releasing their moisture. Continue to cook until they begin to brown and soften.

Pour in the vegetable broth and add the fresh thyme. Bring the soup to a simmer and cook for another 10 minutes, allowing the flavors to blend and the broth to reduce slightly.

Using an immersion blender, blend the soup until it’s smooth and creamy. If you don’t have an immersion blender, you can carefully transfer the soup in batches to a regular blender. Make sure to let the soup cool slightly before blending to avoid splattering.

Once the soup is smooth, stir in the heavy cream for that rich, velvety texture. Then, break the brie into small chunks and stir it into the soup. Allow the brie to melt fully into the soup, creating that creamy, indulgent base.

Taste the soup, and add salt and pepper as needed. Adjust the seasoning to suit your preferences and give the soup one final stir.

Ladle the soup into bowls and garnish with fresh thyme or a drizzle of cream, if desired. Serve it warm with a slice of crusty bread for the perfect meal.