It's smooth, creamy, not exactly bitter (6)
I believe the answer is:
butter
'bitter' is the definition.
The definition and answer 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 cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for butter that I've seen before include "Bread-spread made from milk" , "& 22 Mincepie accompaniment" , "Spread for bread" , "Spread derived from cream" , "Dairy spread" .)