Place the chicken breasts or pork cutlets between parchment paper and pound gently to an even thickness. Season both sides with salt and black pepper.
Prepare three shallow bowls: one with flour, one with beaten eggs, and one with panko breadcrumbs.
Coat each cutlet in flour, dip into the egg, then press gently into the panko until fully coated.
Heat the oil in a deep pan over medium heat until a breadcrumb sizzles immediately when dropped in.
Fry the breaded cutlets for about 3 to 4 minutes per side, turning once, until golden brown and cooked through.
Transfer the katsu to a wire rack or paper towel-lined plate and let rest for 2 to 3 minutes.
Cook the rice with water according to package instructions, then fluff gently once cooked.
In a small bowl, mix ketchup, Worcestershire sauce, soy sauce, and sugar until smooth to make the katsu sauce.
Slice the rested katsu into thick strips using a sharp knife.
Assemble bowls by adding rice, shredded cabbage, sliced katsu, and drizzling with katsu sauce.
