What's for lunch?

Today, as pretty much every day, I am my kids' personal chef; what does that mean? That I absolutely have to make whatever they want to eat, and thank God they are not into junk food anymore! Today they wanted LOMO SALTADO, which is a very common and well known peruvian dish, and since it turned out pretty good according to them (they may be a little biased), I'll share my own personal recipe... I honestly don't know who will read this, but in case any professional chef does, I am repeating what I stated before... MY OWN PERSONAL RECIPE ;)
Recipe for 4
1 Kg. beef (ideally tenderloin)
1/2 Kg. potatoes
1/2 Kg. ripe tomatoes
1/2 Kg. onions
Parsley, salt, pepper, garlic, soy sauce, vinegar, chilli pepper.

Cut the beef in rectangular pieces of 2 by 3 cms. (don't use a ruler, just calculate it with your thumb)
Marinate the beef for an hour in salt, pepper, garlic and soy sauce, at taste, be careful with the sodium though.
Cut the potatoes for french fries (french cut) let them soak in water for a while, then dry them with toilet paper and immediately fry them until golden.
Cut the onions and tomatoes julienne and save them.
Chop the parsley and cut the chilli pepper in brunoise.
Cook the meat on a wok preferably, if you don't have a wok, use a wide, big frying pan.
Heat the oil and add the meat, stirring from time to time, making sure it is golden brown (don't overcook or it'll be hard to chew)/
Once the meat is golden brown, add the onions, and stir to blend.
Add the tomatoes and chilli pepper, continue stirring carefully until it blends.
Add salt, pepper and vinegar to taste, if it looks a little dry, add a little bit more of soy sauce. Cover and let it simmer for 15 minutes (low fire).
Remove from fire, and add the fries and parsley. It should be juicy and brown. Serve with white rice.
Enjoy :)