Choose one of the following methods for preparing the meat:

If slicing into beef strips for marinating:

• Slice partially frozen steak in very thin slices across the grain (It is easiest to cut beef into srips when it is partially frozen). Place beef in zip-style plastic bag and pour 1 cup teriyaki sauce over it. Seal and place in refrigerator to marinate for at least 1 hour and up to 24 hours.

If marinating whole steak:

• Pierce beef with a fork all over one side. Turn to opposite side and pierce all over with fork. Place steak, whole, in a zip-style plastic bag. Pour 1 cup teriyaki sauce over meat in bag, seal bag. Through the outside of the close bag, massage the sauce into the meat a little, then place in refrigerator for at least 1 hour or up to 24 hours.
• Remove beef from marinade; discard marinade.
• Heat a large skillet or a wok over high heat until very hot. Add oil and swirl skillet or wok to coat with oil.
• Add the broccoli and carrots to the pan. Stir-fry for about 2 minutes.
• Add the onions and peppers to the broccoli and carrots and continue to stir-fry just until barely crisp tender. Remove pan from heat and set aside. There is no need to add salt or other seasonings to the vegetables because the teriyaki sauce will have all of the flavors that are needed.

If Using Beef Strips

• Remove vegetables from pan or wok and set the vegetables aside. Add a little more oil to the pan/wok and stir-fry the beef just until it loses it's pink color. 
• Return the vegetables to the pan/wok with the beef, add approximately 3/4-1 cup of teriyaki sauce (or to taste--it can be really strong, so use it judiciously) and stir-fry for a couple of minutes just until the sauce barely reduces and gets a little glossy on the food.

If Using Whole Beef Steak

• Heat a little oil in a grill pan or a frying pan. Remove steak from marinade (discard marinade).  
• Place the steak in the pan and cook for 5-8 minutes on each side, depending on the desired degree of doneness (145-degrees = medium-rare; 160-degrees = medium). I cooked my steak to medium rare because it cooked a little more when I returned it to the vegetables. 
• Remove steak from pan and put on a cutting board to rest for about 10 minutes. Slice into thin strips at an angle against the grain.
  
• Add the beef strips to the vegetables. Add 3/4-1 cup teriyaki sauce (depending on taste preference); stir-fry over medium high heat for a couple of minutes just until the sauce barely reduces and gets a little glossy on the food.
• Serve over hot, cooked rice.