One remarkably aged wine in this (10)
I believe the answer is:
methuselah
'remarkably aged wine in this' is the definition.
The definition suggests a singular noun which matches the answer.
'one' is the wordplay.
I cannot quite see how this works, but
'one' could be 'me' (a setter might use 'one' to humourously mean 'me') and 'me' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for methuselah that I've seen before include "Large wine bottle - very long-lived man" , "so much champagne" , "able to hold a lot of drink" , "Old Testament patriarch (very old when he died!)" , "a lot of bottle" .)