Superior sweets with a twist (4)

I believe the answer is:

smug

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'superior' is the definition.
(I've seen this before)

I don't understand how the rest of the clue works.

(Other definitions for smug that I've seen before include "Self-satisfied, stuffy" , "Overly complacent" , "Full of oneself" , "Self-satisfied and vain" , "irritating expression" .)

I've seen this clue in The Telegraph.

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