Because flank steak has a large surface area, it benefits from marinating to add flavor. This marinade is a combination of Lawry’s® Teriyaki Marinade plus ketchup for added sweetness, and crushed red pepper for heat.
Mix marinade, ketchup, sesame seed and red pepper in small bowl. Reserve 2 tablespoons for brushing. Place steak in large resealable plastic bag or glass dish. Add remaining marinade mixture; turn to coat well.
Refrigerate 30 minutes or longer for extra flavor. Remove steak from marinade. Discard any remaining marinade.
Broil or grill steak over medium-high heat 7 to 8 minutes per side or until desired doneness, brushing with reserved 2 tablespoons marinade mixture. Let stand 5 minutes before slicing.