Sauté Onion and Garlic: In a large pot, heat the butter and oil over medium-high heat. Sauté the onion in the melted butter for 5 minutes until softened. Add the garlic and fry for about 1 minute until fragrant.
Add Mushrooms and Simmer: Add the sliced mushrooms, and fresh thyme. Let it simmer for 5-7 minutes, then add the white wine.
Add Xanthan Gum and Broth: If you like a thicker soup, sprinkle the mushrooms with xanthan gum, stir well, and cook for about 2 minutes. Then, pour in the broth and bring the mixture to a boil.
Simmer the Soup: Once boiling, reduce the heat, cover, and let the soup simmer for 12-15 minutes until it has thickened to your liking.
Add Heavy Cream: Remove the soup from heat and stir in the heavy cream. If you prefer, you can use a stick blender to puree the soup at this stage.
Season and Serve: Taste and adjust the seasoning with salt and pepper if needed. Stir in the remaining fresh thyme and some fresh parsley. Enjoy the warm soup with a slice of buttery, toasted low-carb bread!
