Top item California put inside bread roll (7,3)

I believe the answer is:

bathing cap

'top' is the definition.
(piece of headwear for one's top)

'item california put inside bread roll' is the wordplay.
'item' becomes 'thing' (I've seen this before).
'california' becomes 'ca'.
'put inside' indicates putting letters inside.
'bread roll' becomes 'bap' (I've seen this before).
'thing'+'ca'='thingca'
'thingca' put inside 'bap' is 'BATHING-CAP'.

(Another definition for bathing cap that I've seen is " Swimmer's hair protector".)

I've seen this clue in The Times.

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