Cupcakes-to-be (6)
I believe the answer is:
batter
'cupcakes-to-be' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for batter that I've seen before include "Make crisp and brown" , "sportsman" , "Hit the flour mixture?" , "Beat the cooking mixture" , "Strike with hard blows" .)