Combine ketchup, Worcestershire sauce, oyster sauce and sugar in a small pot over low heat. Stir until sugar has dissolved. Remove from heat.
Transfer sauce to a serving bowl and let cool. Stir in as much ground sesame seeds as desired.
Tonkatsu
Preheat oven to 200C / 400F (190C / 375F if fan-assisted). Line a baking sheet with parchment paper and set aside.
Place the panko in a small frying pan. Add in the oil and cook on medium heat, stirring frequently until the panko is golden brown in colour. Remove from heat and set aside to cool slightly.
Whisk egg, flour, salt, black pepper and cayenne pepper (if using) in a separate, shallow bowl. Set aside.
Rinse and pat-dry pork chops thoroughly with paper towels. Make very shallow slits on the edges of the pork chops to prevent them from curling up during baking.
Pound the pork chops with a mallet on both sides to tenderise the meat (how long to pound is up to you!) You can also place a parchment paper over the pork chops before pounding to prevent the bits of raw meat from flying all over.
Dip the pork chops into the egg-flour batter and let the excess drip off. Dip the pork chops into panko, pressing the panko gently to adhere to the pork chops.
Place the pork chops on the lined baking sheet and bake in the middle rack for 20 to 25 minutes, until the pork chop is cooked. Stick an instant thermometer to the thickest part of the meat and the temperature should register at least 62C / 145F.
Cut the pork chop into thick chunks and serve with rice, freshly shredded cabbage and tonkatsu sauce. Enjoy!