Medieval platter, perhaps found in ditch at the outskirts of Esker (8)
I believe the answer is:
trencher
'medieval platter perhaps found' is the definition.
I can't tell whether this definition defines the answer.
'ditch at the outskirts of esker' is the wordplay.
'ditch' becomes 'trench' (synonyms).
'at' means one lot of letters go next to another.
'the outskirts of' suggests removing the centre (letters on the edges or outskirts are used).
'esker' with its centre removed is 'er'.
'trench'+'er'='TRENCHER'
'in' is the link.
Can you help me to learn more?
(Other definitions for trencher that I've seen before include "Don cap" , "field worker" , "bearer of food" , "Board" , "Plate" .)