Limitlessly extolling the grape? (6)
I believe the answer is:
raisin
'grape?' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Maybe there's a link between them I don't understand?
I don't understand the rest of the clue.
(Other definitions for raisin that I've seen before include "A dried grape used in cake" , "Partially dried grape" , "sultana, say" , "Dried fruit" , "fruit product" .)