1 1/4 lb. flank steak
1/2 c. vegetable oil
1/3 c. soy sauce
1/4 c. red wine vinegar
2 tbsp. lemon juice
1 tbsp. Worcestershire sauce
1 tsp. dry mustard

Combine marinade ingredients in glass or plastic container. Place steak in marinade, turning to coat completely. Marinate covered for at least 4 hours, overnight, refrigerated. Remove steak from marinade and grill 5 minutes on each side so it is browned on the outside but still rare in the center. Cut steak diagonally across the grain into thin slices.