Secure packing chest for gingerbread (6)
I believe the answer is:
parkin
'gingerbread' is the definition.
(I've seen this before)
'secure packing chest' is the wordplay.
'secure' becomes 'pin' (pinning is a kind of securing**).
'packing' indicates putting letters inside.
'chest' becomes 'ark' (ark is a kind of chest).
'pin' enclosing 'ark' is 'PARKIN'.
'for' is the link.
(Other definitions for parkin that I've seen before include "Soft gingerbread" , "Type of gingerbread" , "Ginger oatmeal cake" , "Variety of gingerbread" , "Scottish biscuit" .)