Heat a wok or large frying-pan over high heat until it is hot. Add the oil, and when it is very hot and slightly smoking, add the garlic, ginger and spring onions and stir-fry them for 30 seconds, then add the aubergines and continue to stir-fry for 1 minute. Then add the rest of the ingredients. Turn the heat down and cook uncovered for 10-15 minutes until the aubergine is tender, stirring occasionally.