Christmas cake you will reportedly book (4,3)
I believe the answer is:
yule log
'christmas cake' is the definition.
(I've seen this before)
'you will reportedly book' is the wordplay.
'you will' becomes 'yul' (I can't justify this - if you can you should believe this answer much more).
'reportedly' becomes 'e' (I've seen this in other clues).
'book' becomes 'log'.
'yul'+'e'+'log'='YULE LOG'
Can you help me to learn more?
(Other definitions for yule log that I've seen before include "One burnt at Christmas" , "Large piece of firewood; cake" , "Chunk of wood for the Christmas fire" , "Symbolic item of Christmas season" , "Seasonal Christmas cake" .)