What to do with a pain in the ass cat

Lately one of my cats has decided that when I'm behind a closed door trying to get a good night's sleep, that she's going to meow and bang on the bedroom door all night. Of course I can't let her in because then she raises hell and keeps me up half the night. I've tried yelling at her, I've tried holding back her "treats" and I've even closed her into the other bedroom. I'm about ready to buy something to show her where she's going to go if she keeps it up: