The Dutchman was in the stand for the Premier Sports Cup defeat to Hibs last November before taking over the following week and admitted that the defender was one who caught his eye despite the 3-1 reverse.
Bassey has been a revelation in the latter stages of the season, winning back-to-back man of the match awards after terrific performances in both the Europa League and Scottish Cup finals as well as being named in the Europa League Team of the Season.
Even more impressively, the Nigeria international was played in two different positions after turning out at centre-back in the penalty shoot-out defeat to Eintracht Frankfurt before moving to left-back for the 2-0 extra-time win over Hearts at Hampden.
Van Bronckhorst was fullsome in his praise of the 22-year-old after watching him complete all 240 minutes of both matches just three days apart.
"I am a big fan of Calvin,” said the Rangers boss. “I remember him at Hampden Park when I watched the loss against Hibs in the (Premier Sports Cup) semi-final (before taking over).
"I saw something in him which is rare to see in his age.
"Very mature, very strong, very powerful, it has been a pleasure to work with him and still work with him in the future to make him stronger.
"The development he had this season is tremendous and that's why he played so many good games in Europe.
"He was very impressive on Saturday and he is an important part of the team at the moment."