In a bowl, combine light soy sauce, dark soy sauce, fish sauce, oyster sauce, brown sugar, garlic paste, white pepper and water. Mix well. Add the sliced pork fillet, mix well once again, cover and set aside in the fridge for at least 2 hours or, ideally, overnight.
Heat the oven to the lowest possible setting (ideally around 80c, if your oven has a 'keep warm' mode this can be used too).
Arrange the sliced pork on a wire rack above a baking tray and place in the oven. Bake for 1 hour.
Heat the oil for deep frying to 180c. Carefully drop the pork slices into the hot oil and fry for around 1-2 minutes until the pork is coloured and crispy. Remove the pork slices from the oil, drain off any excess oil and set aside.
In a dry wok over a low heat, add the spring onion and garlic. Stir-fry for 30 seconds until aromatic. Add the cooked pork slices, season generously with the salt & pepper mix and add the dried chilli flakes. Stir-fry for 20-30 seconds, finish with rice wine and serve.
You can find the Chinese salt & pepper mix recipe here.