To make the chilli oil, place the chillies and salt in a mortar and pound with a pestle until crushed. Stir through the olive oil and set aside.
Place the beef, wine, garlic, rosemary and oil in a bowl and toss to coat. Marinate for 15 minutes. Heat butter in a large non-stick frying pan over high heat. Remove beef from marinade and cook for 30 seconds–1 minute on each side for medium-rare. Remove beef from the pan and slice. Add the marinade to the pan and stir to combine. Top the rolls with beef, spoon over the pan juices and chilli oil+, to taste, and serve with lemon wedges.
+ Any leftover chilli oil will keep in the fridge for up to one week.