Preheat a barbecue or large char-grill pan over medium-high heat. Rub steaks with oil and season. Cook steaks for 4-5 minutes each side, or until cooked to your liking. Set aside on a plate loosely covered with foil for 5 minutes.
Spread base of bread with mayonnaise and top with lettuce, beetroot, tomato, pineapple and steak. Top with barbecue sauce. Place bread lid on top and serve.
Tips
Beef rump, sirloin or minute steaks would also work well.
Use your choice of barbecue or tomato sauce.
Add a fried egg or sliced red onion to the sandwich, if desired.
Use fresh pineapple instead of canned, if desired.