Sweet bishop, say, Glaswegian perhaps leading church (12)
I believe the answer is:
butterscotch
'sweet' is the definition.
(butterscotch is a kind of sweet)
'bishop say glaswegian perhaps leading church' is the wordplay.
'bishop' becomes 'B' (abbreviation for bishop in chess).
'say' becomes 'utter' (to utter something is to speak or say it).
'glaswegian perhaps' becomes 'Scot' (glaswegian is a kind of Scot).
'leading church' becomes 'ch' (common abbreviation. I am not sure about the 'leading' bit.).
'b'+'utter'+'scot'+'ch'='BUTTERSCOTCH'
Can you help me to learn more?
(Other definitions for butterscotch that I've seen before include "confectionery" , "Hard brittle toffee" , "Type of toffee" , "Kind of toffee" , "Brittle, yellow-brown sweet" .)