Saute. Add oil to a large dutch oven over medium heat. Once shimmering, add mushrooms and cook until they begin to brown, about 8 minutes. Set cooked mushrooms aside on a plate. Add butter to the dutch oven, along with the onion, garlic, carrots, and celery, and saute until they begin to soften, about 10 minutes.

Simmer. Add mushrooms back to the pan, along with the brother, thyme, Better than Bouillion, xanthan gum,1 1/2 teaspoon salt, and 1 teaspoon pepper. Whisk until the xanthan gum fully dissolves, then add the chicken breast. Bring soup to a boil, then reduce the heat to a gentle simmer. Partially cover the soup and continue to cook for 25-30 minutes, -- you'll know it's ready once the chicken breast is cooked through.

Shred. Remove chicken to a plate, allow it to cool for a few minutes, then shred with 2 forks.

Finishing touches. Add the chicken back to the soup, along with the heavy cream and cauliflower rice. Simmer until the rice is cooked to your liking, about 10 minutes. Adjust seasoning before serving and enjoy!