Drop a line to Danish favourite from The Seafood Restaurant (8)

I believe the answer is:

fishcake

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'drop a line to danish favourite from' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.

'seafood restaurant' is the wordplay.
'seafood' becomes 'fish' (fish is a kind of seafood).
'restaurant' becomes 'cake' (I can't justify this - if you can you should give a lot more credence to this answer).
'fish'+'cake'='FISHCAKE'

'the' is the link.

Can you help me to learn more?

I've seen this clue in The Irish Times.

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