A fan-turbine rotor assembly (24) includes a multitude of turbine blades (34) which each define a turbine blade passage which bleed air from a diffuser section (74) to provide for regenerative cooling. Regenerative cooling airflow is communicated from the radial core airflow passage (80) through the diffuser passages (144), through diffuser aspiration passages (146A, 146B) and into the turbine blade passages (150a). The regenerative cooling airflow exits from the turbine blade passage (150a) and transfers received thermal energy into an annular combustor (30). The received thermal energy is recovered at the highest temperature in the cycle.