Heat oil for deep frying to 180C. Add the cooked pork pieces to a large bowl. Add the egg and mix briefly, then add the custard powder and plain flour, mixing well until the pork pieces are well coated. Carefully drop the pork pieces into the hot oil and fry for 3 minutes or until piping hot and crispy.
Heat a wok or large frying pan over a medium-high heat. Add the vegetable oil and swirl around the pan. Add the sliced onion and carrot and stir-fry for 20 seconds, then add the cooked crispy pork pieces and the chopped garlic in oil. Season generously with salt and pepper mix, add the spring onion and stir-fry for 20 seconds. Finish with the crushed chilli flakes and rice wine and mix well once more.
Pour the salt and chilli crispy pork on to a serving plate. Serve with curry sauce if desired.
This recipe uses slow cooked pork shoulder.