Sought-after item from good pork pie manufacturer returned (5)
I believe the answer is:
grail
'sought-after item' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Perhaps there's an association between them I don't understand?
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for grail that I've seen before include "Object of knightly quest" , "The Holy ..., the legendary chalice used at the Last Supper" , "Arthurian knights' quest" , "See 2" , "Chalice used by Jesus at the Last Supper" .)