500 g (1 1/4 lb) boneless, skinless chicken breasts, thinly sliced at an angle
30 ml (2 tbsp) cornflour
60 ml (4 tbsp) sunflower oil
1 garlic clove, crushed
5 cm (2 in) fresh root ginger, peeled and cut in matchsticks
1 small onion, thinly sliced
1 fresh pineapple, peeled, cored and cubed, or 425 g (15 oz) can pineapple chunks in natural juice
30 ml (2 tbsp) dark soy sauce or 15 ml (1 tbsp) kecap manis
1 bunch spring onions, white bulbs left whole, green tops sliced
salt and freshly ground black pepper