Place the chicken breast between two sheets of parchment paper and pound to an even half-inch thickness.
Submerge the chicken in the buttermilk in a shallow dish and refrigerate for at least 30 minutes.
In a separate shallow bowl, whisk together the 2 tablespoons of arrowroot powder, almond flour, garlic powder, onion powder, paprika, salt, and pepper.
Remove the chicken from the buttermilk, allowing excess to drip off, and dredge thoroughly in the flour mixture, pressing firmly to ensure a thick coating.
Heat the avocado oil in a large skillet over medium-high heat until shimmering.
Carefully place the chicken in the pan and cook for 5 to 7 minutes per side until the crust is deeply golden and the internal temperature reaches 165 degrees.
Remove the chicken to a plate and reduce the skillet heat to medium.
Whisk the almond milk and the remaining teaspoon of arrowroot powder into the pan drippings, scraping up any browned bits from the bottom.
Simmer the gravy for 2 minutes until thickened, season with the remaining salt and pepper, and pour over the crispy chicken.