One writing on special notepaper? (8)
I believe the answer is:
composer
'one writing on special notepaper?' is the definition.
The answer is a person as well as being a singular noun. This is suggested by the definition.
'one writing' is the wordplay.
I cannot really understand how this works, but
'writing' could be 'r' (one of the traditional three R's of education) and 'r' is found within the answer.
The remaining letters 'compose' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for composer that I've seen before include "One writes music" , "eg Hoagy Carmichael" , "Beethoven or Mozart, say" , "Bliss, perhaps" , "One creates music" .)