I do one of two things with my dogs..... Either A) make them leave the room as they finish, or B) make them drop into a down stay and wait quietly until all dogs are finished and I release them all to re-scour the bowls. Currently it is B.
Whatever you do, you need to stop giving them their food and then turning away. It only takes a minute for a dog to eat a day's ration of food....you will waste far less time if you stay present and supervise than by trying to multitask. Put a leash on the offender if needed to control her while she learns.
Also, if she is leaving her plate with food on it, mine lose their bowls if they make a grab for another bowl, or for any reason leave their own. It is the USMC theory of meals...if you look up, you are done eating.