What can go with Coronation: sadly inadequate royal dish (7,1,2,4)

I believe the answer is:

chicken a la king

I'm a little stuck... Click here to teach me more about this clue!

'what can go with coronation sadly inadequate' is the definition.
I can't tell whether this definition defines the answer.

'royal dish' is the wordplay.
I cannot really see how this works, but
'royal' could be 'king' (a king is royal) and 'king' is present in the answer.
This may be the basis of the clue (or it may be nonsense).

Can you help me to learn more?

I've seen this clue in The Times.

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