Cube in sweet sweets (5,6)

I believe the answer is:

after eights

'sweets' is the definition.
(brand of sweets)

'cube in sweet' is the wordplay.
'cube' becomes 'eight' (8 is a cube number).
'in' indicates putting letters inside.
'sweet' becomes 'afters' (both can mean dessert or pudding).
'eight' placed within 'afters' is 'AFTER EIGHTS'.

I've seen this clue in The Guardian.

Want a hint initially instead of a full solution? Install my app