Cook heads of groupers raised in local lake (5)
I believe the answer is:
grill
'cook' is the definition.
(grilling is a form of cooking)
'heads of groupers raised in local lake' is the wordplay.
'heads of' indicates taking the first letters.
'lake' becomes 'l'.
The initial letters of 'groupers raised in local' is 'gril'.
'gril'+'l'='GRILL'
(Other definitions for grill that I've seen before include "pump" , "Broil" , "Cook under direct heat" , "Seriously question" , "rack" .)