Place the steak, garlic, olive oil, vinegar and mustard in a bowl and toss to combine. Cover and refrigerate for 30 minutes. Heat a char-grill pan or barbecue over high heat. Thread the beef onto skewers and char-grill or barbecue for 2–3 minutes each side for medium rare or until cooked to your liking. Serve with rocket leaves, mountain bread and aïoli. Serves 4.