Cabinet's performance on occasion (8)
I believe the answer is:
showcase
'cabinet's' is the definition.
(I've seen this before)
'performance on occasion' is the wordplay.
'performance' becomes 'show' (I've seen this before).
'on' means one lot of letters go next to another.
'occasion' becomes 'case' (both can mean an instance or situation).
'show'+'case'='SHOWCASE'
(Other definitions for showcase that I've seen before include "exhibition place" , "Display cabinet" , "to suit trophy-holder" , "Exhibit, display" , "Play" .)