In macaroni, once, a pungent ingredient (5)
I believe the answer is:
onion
'pungent ingredient' is the definition.
The definition and answer can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps you can see an association between them that I can't see?
'in macaroni once a' is the wordplay.
'in' indicates a hidden word.
'ONION' is hidden within 'macaroni once a'.
Can you help me to learn more?
(Other definitions for onion that I've seen before include "One may be set" , "Tear-jerking bulb" , "Bulb used as a vegetable" , "associated with 26 [TRIPE] ?" , "Alliaceous plant" .)