Place the chicken breast in a shallow dish and pour the buttermilk over it, ensuring it is fully submerged. Let it marinate for at least 30 minutes in the refrigerator.
In a small bowl, whisk together the 2 tablespoons of whole wheat flour, cornstarch, garlic powder, onion powder, smoked paprika, sea salt, and black pepper.
Remove the chicken from the buttermilk, letting any excess drip off, then dredge it through the flour mixture, pressing firmly to ensure an even coating.
Lightly spray the chicken with avocado oil and place it in the air fryer basket. Cook at 375°F for 15-18 minutes, flipping halfway through, until the internal temperature reaches 165°F and the crust is golden brown.
While the chicken cooks, prepare the gravy by melting the ghee in a small saucepan over medium heat. Whisk in the remaining 1 tablespoon of whole wheat flour and cook for 1 minute.
Slowly whisk in the chicken broth, stirring constantly to prevent lumps. Simmer until the sauce thickens to a gravy consistency.
Remove the gravy from the heat and stir in the Greek yogurt until smooth. Season with an extra pinch of black pepper if desired.
Slice the chicken and serve immediately with the warm gravy drizzled over the top.