Most simple pastry dishes covered in pepper (7)

I believe the answer is:

dopiest

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'most simple' is the definition.
Both the answer and definition are superlative adjectives. Perhaps there's a link between them I don't understand?

'pastry dishes covered in pepper' is the wordplay.
'pastry dishes' becomes 'pies' (I've seen this before).
'covered in' means one lot of letters goes inside another.
'pepper' becomes 'dot' (I've seen this in another clue).
'pies' placed into 'dot' is 'DOPIEST'.

Can you help me to learn more?

I've seen this clue in The Independent.

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