Place the chicken breast between two sheets of parchment paper and pound with a meat mallet to an even half-inch thickness.
Place the chicken in a shallow dish and pour the buttermilk over it, ensuring it is fully submerged, and marinate for 20 minutes.
In a separate shallow bowl, whisk together the almond flour, arrowroot powder, garlic powder, onion powder, paprika, sea salt, and black pepper.
Remove the chicken from the buttermilk, allowing excess to drip off, then dredge it thoroughly in the flour mixture, pressing to adhere.
Heat the avocado oil in a large skillet over medium heat until shimmering.
Carefully place the chicken in the skillet and cook for 5 to 6 minutes per side until the crust is golden brown and the internal temperature reaches 165 degrees Fahrenheit.
Remove the chicken from the skillet and set aside to rest on a wire rack.
In the same skillet, whisk in the chicken bone broth and fresh thyme, scraping up any browned bits from the bottom.
Stir in the whole milk and simmer for 3 to 4 minutes until the gravy has thickened to your desired consistency.
Drizzle the warm gravy over the chicken and serve immediately.