I came across this recipe online when I was looking for ways to cook meat (other than fish) with cedar planks. I enjoyed this recipe, but to be honest, it would have been good without the cedar planks too.
IMMERSE plank in water, placing a weight on top of plank to keep it submerged. Soak at least 4 hours or overnight. Meanwhile, mix dressing, onions, parsley, cilantro, garlic and red pepper. Remove 1/2 cup of the dressing mixture; set aside for later use. Pour remaining dressing mixture into large resealable plastic bag; add steak. Seal bag; turn over several times to evenly coat steak with the dressing mixture. Refrigerate at least 2 hours to marinate.
PREHEAT barbecue to high heat. Remove steak from marinade; discard bag and marinade. Grill steak 3 minute on each side; remove from barbecue. Remove plank from water; brush top with oil. Top with steak. Place on grate of barbecue; cover with lid. Reduce barbecue to medium heat.
GRILL 15 to 20 minute or until medium doneness (160ºF). Remove steak from barbecue; discard plank. Cover steak loosely with foil; let stand 5 minute Cut steak into thin slices. Spoon reserved dressing mixture over steak.