Christmas fuel (4,3)
I believe the answer is:
yule log
'christmas fuel' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for yule log that I've seen before include "Seasonal Christmas cake" , "It burns at Christmas" , "Chunk of wood for the Christmas fire" , "Large piece of firewood; cake" , "Something eaten (or burned?) at Christmas" .)