Make the marinade by mixing together the sugar, salt, soy sauce and cornflour slurry. Mix in the pork, let marinate for 20 minutes.
Heat a large frying pan with 1 tablespoon oil over high heat. Stir fry the garlic and eschallot until brown. Fry the pork chops until both sides turn brown, about 3-5 minutes. Turn down the heat to medium-low. Cook the pork chops until done, about 3-5 minutes. Set aside.
Heat the same frying pan with 1 tablespoon oil over high heat. Stir fry onion with some salt until soft, about 3-4 minutes.
Add the ketchup, sugar, soy sauce, vinegar and some hot water until the sauce is at the correct consistency. Turn off the heat. Mix this sauce with the pork chops. Garnish with diced spring onions.