Stir the light soy sauce, wine, sugar, cornflour, dark soy sauce and a pinch of salt in a bowl until smooth. Add the pork and stir to combine. Marinate for 30 minutes.
Step 2 Add oil to a wok to reach a depth of 5cm. Heat the oil to 170°C over medium-high heat (when the oil is ready a cube of bread will turn golden brown in 20 seconds). Deep-fry beans, in 2 batches, for 3 minutes or until tender. Use a slotted spoon to transfer to a plate lined with paper towel.
Step 3 Drain all but 1 tablespoon of the oil from the wok. Add the garlic and chilli flakes and stir-fry for 30 seconds or until aromatic. Add the pork mixture and stir-fry for 3 minutes or until browned. Add the beans and XO sauce and stir-fry until combined. Season with white pepper.