Mix a large gin, for starters, in the mornings (7)
I believe the answer is:
amalgam
'mix' is the definition.
(I've seen this before)
'a large gin for starters in the mornings' is the wordplay.
'for starters' says to take the initial letters.
'in the' means one lot of letters goes inside another.
'mornings' becomes 'maam' (I am not sure about this - if you are sure you should believe this answer much more).
The initial letters of 'large gin' is 'lg'.
'lg' put inside 'maam' is 'malgam'.
'a'+'malgam'='AMALGAM'
(Other definitions for amalgam that I've seen before include "Blend of metals" , "mix" , "mercurial combination" , "Mixture, blend" , "Compound" .)