In charge of gin production? Topping! (5)
I believe the answer is:
icing
'topping' is the definition.
(icing is a kind of topping)
'in charge of gin production?' is the wordplay.
'in charge of' becomes 'ic'.
'production?' is an anagram indicator (I've seen 'production' mean this).
'gin' is an anagram of 'ing'.
'ic'+'ing'='ICING'
(Other definitions for icing that I've seen before include "Top cake layer" , "Maybe Madeira's topping" , "Decorative cake coating" , "Concreted sugar" , "white coat" .)