Inadequate side dish (4)
I believe the answer is:
flan
'dish' is the definition.
(I've seen this before)
'inadequate side' is the wordplay.
'inadequate' means to remove the last letter (only some of the word appears).
'side' becomes 'flank' (I've seen this before).
'flank' with its final letter taken away is 'FLAN'.
(Other definitions for flan that I've seen before include "Open-topped pastry dish" , "Open pastry dish" , "Open pastry dessert" , "Baked and filled pastry case dish" , "Open pastry filled with savouries, fruit or custard" .)