Have your butcher prepare the tournedos steaks for you. This is fillet steak (also known as filet mignon) wrapped in a fine band of pork fat. It is rather expensive, but this is one of the very best cuts. Remove the steaks from the fridge at least 1 hour before using.
Dry both sides of the steaks with absorbant paper, then salt and pepper them.
Cut circles of bread about the same size as the steaks (using a cutter makes this easier) and butter both sides.