Boil the potatoes in a large saucepan of salted, boiling water for 10 minutes, then drain and run under cold water for a few minutes.
Pre-heat the oven to 200° C.
Arrange the shallots in a roasting tin and drizzle with 25ml of the olive oil and sprinkle over the demerara sugar. Dot with the butter and roast for 15-20 minutes.
Meanwhile, rub the rump steaks with the groundnut oil and season generously. Heat a large heatproof frying pan over a high heat until smoking hot. Sear the steaks on both sides for a minute then transfer to the oven to finish cooking for 6-8 minutes depending on desired doneness. Remove when ready and transfer to a warmed plate, covering them loosely with aluminium foil for 5 minutes.
Heat the remaining olive oil in a large frying pan and sauté the potatoes for 4-5 minutes, stirring and tossing occasionally. Remove the shallots from the oven at this point. Season with the parsley and some salt and pepper.
Arrange the steaks with any juices in the middle of serving plates and spoon the shallots and potatoes on either side. Serve immediately.
For top tips on protecting you and your family when preparing raw meat and poultry, visit Food Safety in the Home and view the full Food safety at home video.