Cordial head of office following a horse racing event (8)
I believe the answer is:
amaretto
'cordial' is the definition.
(I know that amaretto is a type of cordial)
'head of office following a horse racing event' is the wordplay.
'head of' suggests taking the first letters.
'following' says to put letters next to each other.
'horse' becomes 'mare' (mare is a kind of horse).
'racing event' becomes 'TT' (Isle of Man Tourist Trophy races).
The first letter of 'office' is 'o'.
'a'+'mare'+'tt'='amarett'
'o' after 'amarett' is 'AMARETTO'.
(Other definitions for amaretto that I've seen before include "Almond-flavoured liqueur" , "rink" , "drink" , "Italian almond liqueur" , "Ma, rotate the almond liqueur" .)