Bishop might be seen in this red hat manufactured in California (9)
I believe the answer is:
cathedral
'bishop might be seen in this' is the definition.
The definition suggests a singular noun which matches the answer.
'red hat manufactured in california' is the wordplay.
'manufactured' is an anagram indicator.
'in' is an insertion indicator.
'california' becomes 'cal' (short for California).
'red'+'hat'='redhat'
'redhat' with letters rearranged gives 'thedra'.
'thedra' inserted into 'cal' is 'CATHEDRAL'.
Can you help me to learn more?
(Other definitions for cathedral that I've seen before include "Car halted badly at the large church" , "Where one worships" , "St Paul's or St Patrick's" , "See 3" , "Christ Church or St Patrick's" .)