Offer a view on pie mixture (5)
I believe the answer is:
opine
'offer a view' is the definition.
(I've seen this in another clue)
'on pie mixture' is the wordplay.
'mixture' indicates anagramming the letters.
'on'+'pie'='onpie'
'onpie' is an anagram of 'OPINE'.
(Other definitions for opine that I've seen before include "Hold forth" , "Express or hold view" , "State as one's opinion" , "Think - express a view" , "Suppose" .)