Mix the steak, soy sauce, sugar, chilli
sauce and vinegar together, and set
aside for 10 mins.
Heat a wok with 1 tsp of the oil. Lift
the steak from the marinade and sear,
in batches, then remove. Add a bit more
oil and fry the ginger until golden. Add
the spring onions and pineapple, and
return the steak to the pan. Stir to heat
through for 1 min, then add any remaining
marinade. Keep stirring until the marinade
becomes thick and everything is hot.
Serve sprinkled with coriander, and with
rice and greens, if you like.