Fish cooked inside and covered in oil (6)
I believe the answer is:
aneled
'fish cooked inside and covered' is the definition.
I can't judge whether this definition defines the answer.
'oil' is the wordplay.
I cannot really understand how this works, but
'oil' could be 'anele' (synonyms) and 'anele' is located in the answer.
A single letter 'd' remains which might be clued in a way I don't see.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Another definition for aneled that I've seen is " oiled as before".)