Melt your butter or oil in a large Dutch oven or heavy-bottom stockpot over medium heat.
Add the onion, carrots, celery, and saute for 5 minutes.
Add the chicken, sea salt, pepper, pressed garlic, and thyme. Cook, stirring often for 6-8 minutes.
Stir in your sliced mushrooms and the bay leaf, then continue to cook, for 8-10 minutes.
Add the aged balsamic and allow it to bubble on high heat to reduce for 2-3 minutes.
Add in your chicken bone broth, and bring the soup to a boil, then reduce the heat and simmer for 20 minutes.
Meanwhile, in a small bowl, whisk your milk of choice and Arrowroot/flour together until smooth.
Add this mixture to your soup and continue to simmer while stirring occasionally for 5 more minutes.
Remove bay leaf before enjoying your soup.
Garnish with parsley and serve hot.
Enjoy!