Mix arrowroot powder with 2 Tbsp cold water to form a slurry. Set aside.
Heat ghee in a skillet on medium heat until melted.
Add shallots, mushrooms, salt, pepper, and garlic to skillet. Add bone broth and top with fresh thyme sprigs. Add in arrowroot slurry and cook several minutes, stirring frequently until sauce thickens.
Serve on top of pork, chicken, or steak.