Place the beef strips in a large bowl. Add the ginger, garlic, rice wine, sesame oil, soy sauce, oyster sauce, sugar, cornflour and peppercorns, and mix together well. Cover and marinate in the fridge for 30 minutes.
Heat the pan until very hot, add 1 tbsp of oil and swirl it around to coat the side. Add the onion, stir fry until translucent and lightly browned.
Add the beef and stir-fry for 6 minutes, or until seared and cooked to your liking