With a very sharp knife cut the top round into 5mm thick slices across the grain. Trim off any fat or sinews. Put between two sheets of plastic film and flatten a little more with a meat hammer or rolling pin. Dip each piece in well seasoned flour, beaten egg and soft white breadcrumbs. Pat off the excess.
Melt a little of the clarified butter in a wide frying pan. Fry the scaloppini, a few at a time, until crisp and golden on one side, then flip over on to the other. Drain briefly on kitchen paper. Serve hot with segments of lemon and spinach with raisins and pine kernels.