"You don't have to sound so surprised," she said without looking up. Granted, she didn't cook dinner very often, so it probably was somewhat surprising. But that wasn't the point. The point was; she was mad.
Ignoring Ron has he took his dinner out of the fridge, Hermione did glance up when she heard the sound of a glass bottle, curious as to what he was drinking. Lucky for him, he had the forethought to pick up butterbeer.
Assuming he had meant it when Ron mentioned eating before he wanted to continue with the ridiculous excuses, she glanced over the top of her book at him when he told her nothing was allowed to leave the room. "Did you even ask if you could send me a message?" Of course not. He would have figured that it would be okay and he would just deal with her later.