Place ⅓ cup cornstarch in shallow bowl.
In second shallow bowl, whisk buttermilk, mustard, and garlic until blended.
Combine cornflake crumbs with remaining cornstarch, ½ teaspoon salt and ½ teaspoon pepper in a shallow dish.
With sharp knife, slice 1/16-inch-deep slits on both sides of pork chops, spaced ½ inch apart, in a crosshatch pattern.
Sprinkle chops with remaining ½ teaspoon salt and remaining ½ teaspoon pepper.
Dredge a pork chop in cornstarch making sure to shake off excess.
Using tongs, coat with buttermilk mixture allowing to excess drip off.
Gently press and coat with cornflake mixture also allowing excess to drop off.
Place wire rack inside rimmed baking sheet and lightly coat wire rack with cooking spray. Repeat with remaining pork chops.
Place each coated chop on top of wire rack until all pork chops are covered. Allow coated pork chops rest for 10 minutes while oil heats.
Heat ½ cup oil in skillet over medium-high heat until shimmering or a drop of water flicked in it dances.
Place pork chops in skillet and cook until golden brown and crispy, 2 to 5 minutes. Carefully flip chops and continue to cook until second side is golden brown and crisp. Using a meat thermometer confirm that the center of each pork chop registers 140 degrees, another 2 to 5 minutes.
Transfer chops to paper towel–lined platter and allow to drain for 30 seconds on each side. Serve and enjoy.