Wiktionary
n. (context idiomatic English) Ideal moment to do something.
Wikipedia
"Golden Opportunity" is an episode of the long-running police procedural television series, The Bill, broadcast on 16 April 2002. The episode is significant in the show's history, as it features the events of the first Sun Hill Fire, which resulted in the death of six officers. The episode attracted 8.6 million viewers, and was the first of the few times computer generated imagery had been used on the show. The imagery was used because producing a real explosion and fireball ripping through the station corridors was not possible.
Usage examples of "golden opportunity".
But you must earn your good fortune by watching closely for the golden opportunity when it presents itself and then seizing it with both hands.
You could just be providing him with a golden opportunity to get all of you at once.
But it was only now that I saw the golden opportunity which every fiber of my being commanded me to seize.
The Guild's blatant charges were a golden opportunity -- perhaps a bit premature, but no matter.