Sooo ...
A light coloured Roman tile outer roof, supported by vented bricks that allow airflow, above a vented attic space, above a concrete ceiling also lined with vented bricks (essentially a second roof).
Then it has external shutters, shades (again with a top of Roman tiles) that stick out enough that sunlight doesn't hit the windows directly through the hottest part of the day.
The walls are thick, double-skinned with an air-gap, and painted white on the outside.
Inside, all foors are tiled over concrete so they act as a heatsink, too. Plus it's built partly into the mountain side.
Since moving in we've added some ceiling insulation, double glazing, and redone the chimney so that it's well sealed and doesn't allow warm air in. Next up is heat exchangers, probably one on each end of the house.