In a medium to large skillet, mix together 2 cups panko and 2 teaspoons canola oil until the oil is evenly distributed through the panko. Heat the skillet over medium heat, and cook the panko, stirring often, until it smells toasted and becomes a golden brown color, about 10 minutes. Remove the skillet from the heat and set the panko aside for now.
Place the pork chops between two layers of parchment paper, plastic wrap, or inside a zipper bag. Using the flat side of a meat tenderizer mallet, flatten the pork chop so that it's approximately ½" (1.25cm) thick. Repeat with the remaining pork chops.
If you don't have a meat tenderizer mallet, use anything sturdy with a flat bottom (just make sure it's food-safe) eg. a sturdy drinking glass or measuring cup, or the bottom of a small skillet or saucepan.
Sprinkle one side of the pork chops with ¼ teaspoon kosher salt and ⅛ teaspoon freshly ground black pepper, then flip the pork chops and repeat with the remaining ¼ teaspoon kosher salt and ⅛ teaspoon freshly ground black pepper.
In a medium bowl, whisk together 3 large eggs, then whisk in ⅓ cup all-purpose flour until there are no lumps remaining. It will form a thick batter-like consistency.
Dip one of the pieces of pork into the egg batter mixture. Ensure that it is fully coated on both sides, but not too thickly coated. Wipe any excess off with a butter knife or spatula, allowing the excess to drip back into the bowl. Now dip the batter-coated pork chop into the toasted panko crumbs, ensuring that both sides of the pork are coated with the crumbs. Lay the pork chop into an air-fryer basket (you may need more than one or multiple batches to cook your pork, depending on the size of your air-fryer). Repeat with the remaining pieces of pork.
Place the air fryer basket(s) into the air-fryer, and cook for 350°F for 15 minutes. If you don't have an air-fyer, cook on a wire rack inset into a baking sheet in your oven on convection mode in a 350°F oven.
While the pork is cooking, make the katsu sauce. Stir together ¼ cup ketchup, 2 Tablespoons soy sauce, 1 Tablespoon mirin, 1 Tablespoon brown sugar, 1 Tablespoon Worcestershire sauce, ¼ teaspoon garlic powder, and ¼ teaspoon onion powder in a microwave-safe bowl or measuring cup. Microwave on high in 30-second intervals until the sauce boils rapidly and thickens slightly, about 2 minutes in total. Stir the sauce after each 30-second interval. Alternatively, cook the sauce in a small saucepan over medium heat until boiling and slightly thickened, stirring often.
Remove the pork from the air-fyer and cut into strips. Serve the pork with rice and salad or shredded cabbage.
Notes
Note: this recipe includes just enough panko and egg-flour batter to coat 1½ pounds of pork. If you decide to use more pork than this recipe, make sure you increase the amounts of panko (and oil), eggs, and flour accordingly.