Preheat your oven to 220°C fan-forced.
Toss the potatoes with olive oil, salt and pepper. Spread onto a lined baking tray and bake for 30–35 minutes or until golden and crispy.
Remove the rump steaks from the fridge 20–30 minutes before cooking. Pat dry and season generously with sea salt and cracked black pepper.
Heat a barbecue or heavy frying pan over high heat. Drizzle the steaks with olive oil.
Cook the rump steaks for 3–4 minutes per side for medium rare, or longer to your preferred doneness.
Transfer the steaks to a plate, top each with a spoonful of garlic butter and allow to rest for 5–10 minutes.
While the steaks are resting, prepare the salad by combining the mixed leaves, cherry tomatoes and red onion.
Cook the onion rings according to packet instructions if using.
Serve the rested rump steaks alongside the crispy chips, fresh salad and onion rings.