Combine the Chilli Butter ingredients and store in fridge until ready to serve. Season the steaks, red peppers and onions with salt, black pepper, balsamic vinegar & oil.
Place the vegetables on the hot barbecue or grill, then add the steaks. Do this in two lots if the barbecue or grill is over-crowded.
Mix the leaves with a little oil, lemon juice and seasoning.
Cut the bread lengthways, fill with the leaves, grilled vegetables, steak and top with butter.