Cook chicken. Leave dripping in the stockpot. Add butter to the stockpot or Dutch oven.
Add mushrooms, onions, celery, and carrots. Cook, stirring occasionally until tender, about five minutes.
Stir in seasoning and thyme. Add arrowroot powder. Stir to incorporated.
Stir in chicken broth and cooked chicken. Bring to a simmer. Let thicken 4 or 5 minutes. Add cream. Continue to cook until slightly thickened. Add fresh parsley and serve.