Something sweet I put in memo (8)
I believe the answer is:
noisette
'something sweet' is the definition.
(I know that noisettes are sweet)
'i put in memo' is the wordplay.
'put' becomes 'set' (both can mean to place or position).
'in' indicates putting letters inside.
'memo' becomes 'note' (I've seen this before).
'i'+'set'='iset'
'iset' put into 'note' is 'NOISETTE'.
(Other definitions for noisette that I've seen before include "Small round cut of meat" , "Small piece of boneless lamb" , "Chocolate; piece of meat" , "Some rolled meat" , "Hazelnut chocolate" .)