We're told to leave the course (7)
I believe the answer is:
dessert
'the course' is the definition.
(dessert is a kind of course)
'we're told to leave' is the wordplay.
'we're told' indicates a 'sounds like' (homophone) clue.
'to leave' becomes 'desert' (desert can mean to leave or abandon).
'desert' is a homophone of 'DESSERT'.
(Other definitions for dessert that I've seen before include "tart?" , "Fruit and nuts, perhaps" , "Pudding, sweet" , "Charlotte maybe" , "Fool possibly" .)