Marinating flank steak for one to three hours before grilling will tenderize it and give added flavor.
Use this marinade for up to 3 pounds of flank steak.
1/4 cup olive oil
1/4 cup balsamic vinegar
1/4 cup Worcestershire sauce
1/4 reduced-sodium soy sauce
2 teaspoons Dijon mustard
2 teaspoons finely minced garlic (2 garlic cloves)
1/2 teaspoon salt
1/2 teaspoon black pepper
1/2 teaspoon dried thyme
Whisk all ingredients together in a small bowl or 2-cup Pyrex measuring cup. Pour the mixture into a gallon Ziploc bag. Add up to 3 pounds of steak, and refrigerate one to three hours.