In a large saucepan, cook the spaghetti in lightly salted water until just done; drain and keep warm.
Heat the oil in a wok or large non-stick pan.
Add the onion, ginger, garlic and steak. Stir-fry for three to five minutes over medium heat or until the steak is nearly done.
Add the vegetables and stir-fry until just done. Add a sprinkling of water if necessary.
Blend the soya sauce, cornflour and reserved asparagus liquid until smooth and add to the stir-fry.
Stir until the mixture comes to the boil and thickens.
Add the spaghetti and stir until heated through.
Nutritional value per serving
Glycaemic index 31, fat 9 g, carbohydrate 54 g, fibre 4 g, protein 24 g, kJ 1 621, One serving = 3 starch, 2 ½ protein.