The head after tongue -- what to put it on, once sliced? (6,4)
I believe the answer is:
french loaf
'what to put it on once sliced?' is the definition.
(type of bread)
'the head after tongue' is the wordplay.
'the head' becomes 'loaf' (slang term for the head).
'after' means one lot of letters go next to another.
'tongue' becomes 'french' (French is an example).
'loaf' after 'french' is 'FRENCH LOAF'.
(Other definitions for french loaf that I've seen before include "Long crusty bread" , "pain?" .)