A small prime rib beef roast can be grilled or roasted to perfection — even if cooked from frozen.
Rub roast garlic, salt and pepper. Insert meat thermometer sideways into centre of roast so that shaft is not visible, avoiding fat and bone.
Place drip pan containing 1/2 inch (1 cm) water under grill on one side of the barbecue. Heat barbecue to 400°F (200°C), using medium-high heat. Place roast on grill over flame and cook for 5 minutes per side. Move roast to grill over the drip pan; turn heat off under just the roast.
Cook in closed barbecue, maintaining constant heat, until thermometer reads 145°F(63°C) for medium-rare (about 50 minutes) or cook to desired doneness. Remove roast to cutting board; tent with foil for 5 to 10 minutes.