Step 1 Preheat oven to 220ºC. Place potatoes onto a baking tray. Bake for 40-45 minutes, or until golden and crispy.
Step 2 Meanwhile, combine olive oil, lemon juice, garlic, oregano and some pepper. Rub herb mixture over lamb roast.
Step 3 Place lamb onto a rack in a roasting dish. Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done. For accuracy, use a meat thermometer. (For ideal temperatures, see Your guide to healthier roasts.)
Step 4 Remove lamb from oven, cover loosely and rest for 10 minutes.
Step 4 Remove potatoes from oven, slice lamb and spoon over remaining oregano mixture juices. Serve lamb with roasted jacket potatoes and steamed vegetables.