Mince remains hot to start with (4)
I believe the answer is:
hash
'mince' is the definition.
(I've seen this in another clue)
'remains hot to start with' is the wordplay.
'remains' becomes 'ash' (remains of a fire).
'hot' becomes 'h' (abbreviation eg on taps).
'to start with' means one lot of letters go next to another.
'ash' put after 'h' is 'HASH'.
(Other definitions for hash that I've seen before include "Mess, botch" , "Drug" , "What signifies a number" , "reheated meat and vegetables" , "Weed" .)