Are porterhouse steak and scotch fillet essentially from the same piece of beef?
Scotch filet, like you said, is a ribeye steak. That is quite different from a porterhouse. A porterhouse is a bone-in steak with a strip steak on one side and a filet (what a filet mignon is cut from, also known as tenderloin) on the other. It is similar to a T-bone steak but has a significantly larger filet portion and is thus a more desirable steak. A Scotch filet, or ribeye, come from along the ribs. Therefore a porter house is much leaner (the only significant fat is along the outer edge of the strip), while a Scotch filet is well-marbled(fattier). They are both excellent cuts in their own right, but definitely not the same. Hope this helps.