Edit epistle, excising half of it, leaving only a little meat (6)
I believe the answer is:
cutlet
'meat' is the definition.
(cutlet is a kind of meat)
'edit epistle excising half of it leaving only a little' is the wordplay.
I cannot really see how this works, but
'edit' could be 'cut' (cutting is a kind of editing) and 'cut' is found within the answer.
'it' could be 't' (abbreviation. e.g. in 'tis) and 't' is found in the answer.
'little' could be 'l' (abbreviation for little) and 'l' is located in the answer.
A single letter 'e' remains 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 cutlet that I've seen before include "Slice of veal" , "Cut of meat" , "Piece for a few swallows only" , "Thin piece of rib-meat" , "Piece of rib with its meat" .)