Petty officer on ship heartens wretch with creamy dessert (6)
I believe the answer is:
posset
'creamy dessert' 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 an association between them I don't understand?
'petty officer on ship heartens wretch' is the wordplay.
'petty officer' becomes 'po' (naval abbreviation).
'on' means one lot of letters go next to another (in a down clue, letters appear on others).
'ship' becomes 'SS' (prefix in ship names eg SS Great Britain).
'heartens wretch' becomes 'et' (I can't justify this - if you can you should believe this answer much more).
'po'+'ss'+'et'='POSSET'
'with' acts as a link.
Can you help me to learn more?
(Other definitions for posset that I've seen before include "As relief for cold" , "So step on curdled milk once used as a cold remedy" , "Curdled milk drink" , "Sweet spiced milk curdled with alcohol" .)