cooking time for lamb rump roast
Method. 1  Preheat the oven to 220ÂºC. 2  Brush the roast lightly with oil and season with salt and pepper. 3  Place the lamb on a rack in a roasting dish. 4  Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done. Preheat the oven to 220ÂºC. 2  Brush the roast lightly with oil and season with salt and pepper. 3  Place the lamb on a rack in a roasting dish. 4  Roast for 15 minutes for rare, 25 minutes for medium, or 30 minutes for well done.