Lacier pants, that's sweet (6)
I believe the answer is:
eclair
'sweet' is the definition.
The answer and definition can be both things that one consumes for nourishment as well as being singular nouns.
Perhaps there's an association between them I don't understand?
'lacier pants' is the wordplay.
'pants' indicates anagramming the letters (UK informal term for 'nonsense' or 'rubbish').
'lacier' with letters rearranged gives 'ECLAIR'.
'that's' acts as a link.
Can you help me to learn more?
(Other definitions for eclair that I've seen before include "Soft cream cake" , "cream-cake" , "Choux pastry cream cake" , "Food" , "comedian Jenny?" .)