Asparagus tip in tempura, battered against the flow (8)
I believe the answer is:
upstream
'against the flow' is the definition.
(I've seen this before)
'asparagus tip in tempura battered' is the wordplay.
'tip' suggests the final letters.
'in' is an insertion indicator.
'battered' is an anagram indicator.
The final letter of 'asparagus' is 's'.
'tempura' is an anagram of 'uptream'.
's' going into 'uptream' is 'UPSTREAM'.
(Other definitions for upstream that I've seen before include "Away from the sea" , "away from estuary?" , "Going back to the source" , "Current trend is not" , "Towards (river's) source" .)