Composer's scheme — nonsense written about it (7)
I believe the answer is:
copland
'composer's' is the definition.
(I've seen this before)
'scheme nonsense written about it' is the wordplay.
I cannot quite understand how this works, but
'scheme' could be 'plan' (synonyms) and 'plan' is present in the answer.
'nonsense' could be 'cod' (I've seen this in other clues) and 'cod' is found in the leftover letters.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for copland that I've seen before include "Aaron, perhaps" , "Aaron -, US composer" , "Creator of notes" , "Aaron -; Rodeo, Billy the Kid composer" , "Notes expert" .)