To be clear, Angela Molina was the one that bowed out of the film. It was sad that she put Luis Bunuel through all that trouble, but luckily he was genius to come up with the idea of two actresses after a couple of dry martinis.
Bunuel wrote in his autobiography that as he got older he was glad to be rid of desire. He felt it was something that controlled him. He finally felt free. It's no mean irony that women's desire often goes the opposite way.
Buñuel's first film came out in the silent era, and his last the same year as Star Wars. In between are, by my estimation, at least 7 masterpieces and many more that come close. This is the perfect swansong, a playful, dark, bemused look at eternally thwarted desire and a killer satire of the male gaze. The double actresses are a brilliant conceit. Even pushing 80, Buñuel kept searching all the way until the end.
Seems restrained at first but it is a very cerebral film dealing with humanity's inability to rationalize its more primitive desires. The casting of the two actresses is testament to the duality inherit in a given person. The political strife that unfolds in the background is used to a great effect, where even acts of terrorism seem secondary to the complexity of desire. Masterpiece but needs another watch.