No elm can produce one! (5)
I believe the answer is:
lemon
'produce one' 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?
'no elm can' is the wordplay.
'can' indicates anagramming the letters (I've seen 'canned' mean this (canned can mean drunk)).
'no'+'elm'='noelm'
'noelm' anagrammed gives 'LEMON'.
Can you help me to learn more?
(Other definitions for lemon that I've seen before include "Tone" , "Fruit (which is proverbially "the answer")" , "Pale yellow, as of citrus fruit" , "Fruit squeezed on Pancake Day?" , "something defective" .)