Place the chicken breast between two sheets of parchment paper and pound with a meat mallet to an even half-inch thickness.
In a shallow bowl, whisk together the buttermilk, garlic powder, onion powder, and paprika.
Place the chicken in the buttermilk mixture and let it marinate for at least 15 minutes in the refrigerator.
In a separate shallow dish, whisk together the 2 tablespoons of whole wheat flour, sea salt, and black pepper.
Remove the chicken from the buttermilk, letting any excess liquid drip off, and dredge it thoroughly in the seasoned flour until fully coated.
Heat the avocado oil in a medium skillet over medium heat and sear the chicken 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 it aside on a plate to rest.
In the same skillet, whisk the remaining 0.5 tablespoons of flour into the pan drippings for 1 minute, then slowly whisk in the milk until the gravy is smooth and thickened.
Pour the warm gravy over the chicken and serve immediately.