2) Combine the jus ingredients in a medium saucepan; bring to the boil then reduce the heat and simmer for 15-18 minutes or until the liquid is reduced to 240ml.
3) Meanwhile prepare the onions; heat the oil in large nonstick frying pan over a medium heat. Add the onion and cook 5-7 minutes or until tender, stirring occasionally.
4) Reduce the heat, sprinkle with demerara sugar and continue cooking for about 10 minutes or until very tender and golden brown, stirring often. Remove from the pan and keep warm.
5) Heat the same pan over a medium heat. When hot, place the steaks in the pan and cook 13-15 minutes for medium rare to medium, turning occasionally. Remove the pan from the heat and allow to stand for 5 minutes.
6) Preheat the grilling element. Cut the bread in half crosswise; cut each half crosswise in half again forming quarters. Split each quarter horizontally in half.
7) Place the bread cut side up on a rimmed metal baking tray, so the surface of the bread is 7 1/2-10cm from the heat. Toast for 30 seconds to 1 minute or until lightly browned.
8) Carve the steaks into thin slices. Place equal amounts of steak slices on the bottom portions of bread. Top evenly with caramelised onion and cheese and then close the sandwich. Ladle hot jus into cups for dipping, sprinkling chopped coriander over the top.
Cook's tips: 450g boneless beef top sirloin steak, cut 1 1/2cm thick, may be substituted for shoulder top blade (flat iron) steaks. Pan-fry 10013 minutes for medium-rare to medium, turning once.
Four crusty french rolls (about 60g each) may be substituted for the ciabatta bread. Split in half, toast and fill as directed above.