Sweet little letter containing crossword compiler’s admission? (8)
I believe the answer is:
noisette
'sweet' is the definition.
(I've seen this before)
'little letter containing crossword compiler's admission?' is the wordplay.
I cannot really see how this works, but
'letter' could be 't' and 't' is found in the answer.
'compiler's' could be 'is' (the person who is writing these clues) and 'is' is found in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for noisette that I've seen before include "Some rolled meat" , "Hazelnut chocolate" , "Chocolate made with hazelnuts" , "Rolled piece of lamb; nutty sweet" , "Chocolate; piece of meat" .)