Although it takes a bit of planning ahead, this is a great Sunday dinner option because it doesn't take a lot of work or effort.
1 to 2 pound beef flank steak
1/4 to 1/3 cup vegetable oil
1 to 2 teaspoons vinegar
1 to 2 cloves garlic, minced
Score steak on both sides. Place meat in a plastic bag and set in a bowl. Combine oil, vinegar and garlic; pour over meat. Close bag and let stand at room temperature 2 to 3 hours, turning several times. Remove meat from marinade and place on rack in broiler pan. Broil 3 inches from heat 4-5 minutes. Sprinkle with salt and pepper and turn. Broil 4-5 more minutes for medium rare. Season to taste with salt and pepper. Carve in very thin slices diagonally across the grain.