A couple of things I would suggest:
1) have her pause the swing right at contact with the ball- a lot of people a mental image of where they should be htting, but have no body awareness of where they are actually hitting the ball. With the pause, you can then take corrective input (extension of the arms/ move the contact point forward). I like the mental image that your are throwing the head of the racquet into the ball.
2) I like to drill the backhand with only a couple of fingers on the forehand hand (left hand in the case of your daughter), so the backhand side hand has to do the work of steering. I find that too much forehand dominance makes the shot too wristy.
3) I would flatten/shorten that stroke by moving her forward and into the court and practice hitting balls on the rise using a very short take back (basically a shoulder turn to prepare the racquet head to the height of the ball). MAke sure she is hitting through the ball and using with a good follow through.