I'm not fat...~

She's made of cake, her mother was the candy witch before Hansel and Grettle got at her...

She's always been vengeful for her mother. However she's very helpful, and doesn't hurt those who don't deserve it.
You might be thinking "What on earth can a girl made of cake do to people"

Well besides the fact she's not only good at cooking, she's good at potion making... As she has her mother's old spell book...
So yeh. She poisons cakes.