Whisk together the soy sauce, oyster sauce, sugar and chilli flakes in a small mixing bowl. Place the steak strips in a shallow dish and cover with the marinade. Toss to combine well, then cover and chill for 30 minutes.
After marinating, remove from the fridge and allow to come up to room temperature. Sit the beef in a sieve placed over a bowl to drain from the marinade.
Heat the groundnut oil in a large wok over a moderate heat until hot. Stir-fry the beef for 2-3 minutes, then add the shallots, spring onions and ginger. Continue to cook for a further 2-3 minutes, then remove from the heat and sprinkle over the chopped coriander.
Serve with hot rice and garnish the stir-fry with a sprig of coriander.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home.