Step 1

Rub roast garlic, salt and pepper. Insert meat thermometer sideways into centre of roast so that shaft is not visible, avoiding fat and bone.

Step 2

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.

Step 3

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.