Some pig ate aubergine cake (6)
I believe the answer is:
gateau
'cake' is the definition.
(gateau is a kind of cake)
'some pig ate aubergine' is the wordplay.
'some' says the answer is hidden in the clue (some of the parts of the word are used).
'GATEAU' is hidden within 'pig ate aubergine'.
(Other definitions for gateau that I've seen before include "Cake (from the Black Forest?)" , "Black Forest dessert" , "Calorie-laden cake" , "Fancy cake" , "named for Black Forest?" .)