To act as PIC of a high-performance airplane you must have:
a: Logged and received ground and flight training from an authorized flight instructor in a high-performance airplane, or in a flight simulator or flight training device that is representative of a high-performance airplane and have been found proficient in the operation of systems of that airplane.
b: Received and logged a one-time endorsement in your logbook from an authorized instructor who certifies you are proficient to operate a high-performance airplane.
Hope that helps. It's from my PPL oral exam guide.