Cheese plates thrown in contest (12)
I believe the answer is:
steeplechase
'contest' is the definition.
(steeplechase is a kind of contest)
'cheese plates thrown' is the wordplay.
'thrown' is an anagram indicator.
'cheese'+'plates'='cheeseplates'
'cheeseplates' anagrammed gives 'STEEPLECHASE'.
'in' is the link.
(Other definitions for steeplechase that I've seen before include "Horse race with ditches and hedges" , "Horse race with jumps and ditches" , "run?" , "Race over fences" , "Race with obstacles to be jumped" .)