Slice of food approaching empty cakehole (5)
I believe the answer is:
piece
'slice' is the definition.
(I know that slice can be written as piece)
'food approaching empty cakehole' is the wordplay.
'food' becomes 'pie' (pie is a kind of food).
'approaching' is a charade indicator (letters next to each other).
'empty' suggests removing the centre.
'cakehole' with its centre taken out is 'ce'.
'pie'+'ce'='PIECE'
'of' is the link.
(Other definitions for piece that I've seen before include "Separate part of a whole" , "Portion; musical work" , "Chessman - part - firearm" , "See 3" , "man on board" .)