Get gruyere to start, before grating (5)
I believe the answer is:
grasp
'get' is the definition.
(I've seen this in another clue)
'gruyere to start before grating' is the wordplay.
'to start' suggests taking the first letters.
'before' means one lot of letters go next to another.
'grating' becomes 'rasp' (rasp can mean a grating noise).
The initial letter of 'gruyere' is 'g'.
'g'+'rasp'='GRASP'
(Other definitions for grasp that I've seen before include "Hold firmly; understand" , "Hold tightly" , "Seize, hold firmly" , "Understand; take in hand" , "Appreciation" .)