Cook noodles in a large saucepan of boiling water until al dente (2-3 minutes). Drain, refresh under cold running water and set aside to drain, then toss with 1 tbsp vegetable oil in a bowl to prevent sticking. Set aside

Heat remaining oil in a wok over high heat, add spring onion and ginger and stir fry until fragrant (20 seconds or so). Then add char siu and stir to warm for 1-2 minutes. Add stock, oyster sauce, soy sauce and sesame oil, and bring to the boil. Stir in noodles and serve warm.