Serve sugarless cola without opening snacks (7,5)

I believe the answer is:

sausage rolls

'snacks' is the definition.

'serve sugarless cola without opening' is the wordplay.
'serve' is an anagram indicator (I've seen 'served' mean this).
'without opening' means to remove the first letter.
'cola' with its first letter taken away is 'ola'.
'sugarless'+'ola'='sugarlessola'
'sugarlessola' with letters rearranged gives 'SAUSAGE-ROLLS'.

I've seen this clue in The Guardian.

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