Run the Chateaubriand Roast on both sides with salt and pepper. Place meat in shallow pan. Add bay leaf, onions, and garlic. Drizzle with oil. Cover and marinate in refrigerator for 2-3 hours, turning meat once or twice. Drain meat and discard marinade. Grill over medium-hot charcoal fire, turning to brown evenly. Continue cooking over indirect heat in covered grill about 25 minutes, turning frequently, until meat is desired degree of doneness.