1.Adjust an oven rack to the middle position and preheat the oven to 400 degrees. Line a rimmed baking sheet with parchment paper and add a wire rack to the top.
2.Combine the panko and oil in a frying pan and toast over medium heat until golden brown. Transfer panko into a shallow dish and allow to cool.
3.Get rid of the extra fat and make a couple of slits on the connective tissue between the meat and fat. This will prevent the tonkatsu from curling.
4.Pound the meat with a meat pounder. Mold the extended meat back into original shape with your hands. Sprinkle salt, black pepper, and garlic powder on both sides of each chop.
5.Add the flour into a shallow bowl. Crack the egg into another shallow bowl and beat gently until combined.
6.Dredge each pork piece in the flour to coat completely and pat off the excess flour. Then dip into the beaten egg and finally coat with the toasted panko. Press on the panko flakes to make sure they adhere to the pork.
7.Place the pork on the wire rack. Bake until the pork is no longer pink inside, about 20 minutes. Cut tonkatsu into 1 inch pieces by pressing the knife directly down, not moving back and forth. This way the panko will not come off. Transfer to a plate and serve immediately.