Ascetic Jew eating cold meat (7)
I believe the answer is:
essence
'meat' is the definition.
(I know that meat can be written as essence)
'ascetic jew eating cold' is the wordplay.
'ascetic jew' becomes 'essene' (I can't explain this - if you can you should believe this answer much more).
'eating' means one lot of letters goes inside another.
'cold' becomes 'C' (eg on taps).
'essene' going around 'c' is 'ESSENCE'.
Can you help me to learn more?
(Other definitions for essence that I've seen before include "quality of perfume?" , "Crux" , "Defining quality" , "Vital element" , "Attar" .)