A portion of crab bisque for teacher (5)
I believe the answer is:
rabbi
'teacher' is the definition.
(Jewish teacher)
'a portion of crab bisque for' is the wordplay.
'a portion of' indicates the answer is hidden within the clue.
'RABBI' is hidden in the letters of 'crab bisque for'.
(Other definitions for rabbi that I've seen before include "Religious scholar" , "Jewish minister" , "A Jewish clergyman" , "Hebrew scholar" , "Sacks, for example" .)