1.Slice ginger thinly; stack slices, then slice again into thin slivers.
2.Heat half of the oil in wok; stir-fry beef, in batches, until browned all over.
3.Heat remaining oil in wok; stir-fry ginger and garlic until fragrant. Add beans; stir-fry until just tender.
4.Return beef to wok with onion, sugar and sauces; stir-fry until sugar dissolves and beef is cooked as desired. Remove from heat; stir through basil.