Reserve 2 tablespoons flour, and set aside. Place remaining flour in a shallow dish.
Combine Cajun seasoning, garlic powder, and pepper. Rub pork chops evenly on both sides with seasoning mixture.
Dip pork in buttermilk; dredge in flour. Lightly coat both sides of pork with cooking spray.
Cook pork, in batches, in hot oil in a large heavy skillet over medium-high heat 5 minutes on each side or until golden brown. Drain on paper towels.
Add reserved 2 tablespoons flour to pan drippings in skillet; stir in milk and salt, and cook, stirring constantly, until thickened and bubbly. Serve immediately with pork. Garnish, if desired.