Mould in bread, cut end off crust (4)
I believe the answer is:
cast
'mould' is the definition.
(I know that mould can be written as cast)
'bread cut end off crust' is the wordplay.
'bread' becomes 'cash' (I've seen this in another clue).
'cut' means to remove the last letter.
'end off' suggests the final letters.
The last letter of 'crust' is 't'.
'cash' with its final letter taken away is 'cas'.
'cas'+'t'='CAST'
'in' is the link.
(Other definitions for cast that I've seen before include "discarded" , "Personnel in a play" , "Discard; actors (in play)" , "protection from injury" , "Throw - actors in play" .)