Trim off fat from the pork. Make a few slits without cutting through the meat. Then pound the meat with a meat pounder until desired thinness is achieved. See note.
Squeeze out the juice from the grated ginger and drizzle over the meat, and lightly sprinkle with salt and pepper.
Thinly slice the cabbage leaves, and soak in cold water with a couple of slices of lemon. Drain well before serving.
Place the flour and breadcrumbs in two separate plates, and the egg in a shallow bowl.
Dredge the meat in flour, shaking off excess flour. Dip in the egg, and then dredge in the breadcrumbs, pressing down gently on the meat for a good coating of breadcrumbs. Repeat for the remaining pieces.
Add 4 cups of oil to a deep fryer, wok or a deep pan. Heat over high heat to 325°F. Drop the meat in the oil. Do not fry more than 2 pieces at a time. Cook until lightly golden brown, flipping once, about a minute each side. The cooking time will depend on the thickness of the meat.
Remove, and drain on a wire rack or a paper towel. Reheat the oil to 325°F. Add the meat and deep fry again for a minute until lightly golden brown. Drain on a wire rack or drain on paper towel again.
Cut each cutlet into small pieces and serve on plate with cabbage slaw with the optional lemon and cucumber slices for garnish. Serve hot with the katsu along with rice and kimchi, if desired.
Notes
Korean markets usually sell pork cutlets specifically prepared for tonkatsu with slits all over on the meat. The slits help tenderize the meat and keep it nice and flat when fried. Koreans typically make tonkatsu thinner and larger than the Japanese version, but it’s up to you how thin you want to make.