What is required for an EASA pilot to fly an airplane with retractable gear, flaps and variable pitch prop?
I can't find any equivalent definition for what the FAA defines as a complex aircraft for the purposes of endorsements. EASA defines a complex aircraft completely differently.

“‘complex motor-powered aircraft’ shall mean:
(i) an aeroplane:
with a maximum certificated take-off mass exceeding 5700 kg, or
certificated for a maximum passenger seating configuration of more
than nineteen, or certificated for operation with a minimum crew of at
least two pilots, or equipped with (a) turbojet engine(s) or more than
one turboprop engine, or
(ii) a helicopter certificated:
for a maximum take-off mass exceeding 3175 kg, or for a maximum
passenger seating configuration of more than nine, or for operation
with a minimum crew of at least two pilots, or
(iii) a tilt rotor aircraft;”