Stir fried beef

1) Put the beef in a shallow bowl and add soy sauce, coating the meat well.
2) Leave to marinade for at least 30 minutes.
3) Cut leeks and carrots into matchstick sized strips.
4) Slice mushrooms, chop pepper and cut ginger into thin strips.
5) Heat oil in a wok or frying pan.
6) Drain beef and add to wok, reserving marinade.
7) Stir fry for 2-3 minutes. Remove with a slotted spoon and keep warm.
8) Add vegetables and stir fry for 3-4 minutes, then add beef, marinade and bean sprouts.
9) Cook for 2-3 minutes until vegetables are crisp.
10) Season and serve.