Marinate a flank steak overnight or for at least 8 hours in the following, after poking holes in it with a fork:
- 1/8 cup olive or vegetable oil
- 1/4 cup of vinegar, preferably wine vinegar or balsalmic
- 2 T soy sauce
- 2 T Worcestershire sauce
- juice of half a lemon
- Substantial sprinkle of garlic powder
I usually put this all, along with the steak, in a gallon freezer bag and turn it over once or twice to get all sides.
Broil until outside done and inside still very pink-- they will continue cooking while you slice them and put on the warm juices when you serve it. (Reserve juices in broiler pan.) Take out and put on a cutting board, slide against the grain at an angle, into 1/4 to 1/2 inch slices. Add a small amount of water into broiler pan with juices, stir around in pan, and then put into a gravy boat or other container you can heat up and pour over slices steak.
You can add other seasoning to marinate, but I like it this way.