Something tasty in City den (6)

I believe the answer is:

eclair

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'something tasty' is the definition.
I can't tell whether this defines the answer.

'city den' is the wordplay.
'city' becomes 'EC' (the City of London postcode).
'den' becomes 'lair' (synonyms).
'ec'+'lair'='ECLAIR'

'in' acts as a link.

Can you help me to learn more?

(Other definitions for eclair that I've seen before include "Lacier type of confection" , "Finger-shaped cake with cream and chocolate" , "Oblong cream puff" , "Long chocolate cake for Claire" , "Lacier type of cake" .)

I've seen this clue in The Sun.

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