Cook the spaghetti in a large pan
in plenty of boiling, salted water for 12-13 minutes, or accordingly
to the directions on the packet, until just tender.
Drain and keep warm.
In a large pan, heat the oil, then
add the onion and stir over moderate heat for 2 minutes.
Add the leeks and carrots and
continue stirring for 2-3 minutes, then add the garlic and ginger.
Stir fry for 1 minute more, then
add the soy sauce, sherry and salt and pepper.
Stir, allow just to heat through,
then pour over the spaghetti.