This was a favorite at our house growing up. Really easy to make.
1 flank steak
1/4 cup soy sauce (reduced salt)
1/4 cup mirin cooking wine
1 T. rice vinegar
Mix together the soy sauce, mirin, and rice vinegar in a plastic bag. Marinate the steak in the liquid for 8-24 hours, turning occasionally. Remove from bag 15 minutes before cooking and let rest.
Broil the steak on the top shelf of the oven for 3-5 minutes per side. Remove from oven, let rest for 5 minutes, then carve into thin strips.
Serve atop stir fried noodles with vegetables.
P.S. The marinade makes a fine sauce for the noodles. Just throw it in the wok when you stir fry the noodles. Make sure it boils thoroughly