Grouse fitting tray, eviscerated for burger (4,5)

I believe the answer is:

beef patty

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'burger' is the definition.
Both the answer and definition are singular nouns.
Maybe they are linked in a way I don't understand?

'grouse fitting tray eviscerated' is the wordplay.
'grouse' becomes 'beef' (synonyms).
'fitting' becomes 'pat' (I am not sure about this - if you are sure you should believe this answer much more).
'eviscerated' suggests removing the centre (the word is disembowelled of its inside letters).
'tray' with its middle removed is 'ty'.
'beef'+'pat'+'ty'='BEEF PATTY'

'for' acts as a link.

Can you help me to learn more?

I've seen this clue in the Sydney Morning Herald.

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