Heat an cast-iron griddle until it is smoking. While this is happening, toast strong white bread – a good sourdough mostly likely or something like Philippa’s Pane Toscana. Have ready beetroot, tinned, of course, sliced tomato, onion and tomato sauce. While you are assembling these things onto the toast, which you will first butter, you have put a little ghee into the griddle and then straight away thinly sliced fillet steak. It needs just a moment on each side.
What is thinly sliced? To taste. We are Australian. We do not want one of those American style sandwiches that are too fat to eat. A lot thinner than one would slice fillet steak for, say, pepper steak, where one might wish it to be a couple of inches thick.
Please don’t put rocket on it. There is nothing green about a steak sandwich.