Earwig and the Witch by Diana Wynne Jones
My rating: 4 of 5 stars
Strong-willed orphan Earwig is adopted by a witch and a temperamental man called the Mandrake: she must use all her wits to gain the upper hand in her odd new home.
Earwig has carved out a comfortable niche for herself at the orphanage she's grown up in and has no intention of allowing herself to be adopted. So you can imagine her surprise when she is swept off to a new home and quickly discovers that her adoptive mother is a witch who wants to use her for free labor. Earwig is not amused.
It's marked with all of Diana Wynne Jones's usual wit and charm, and it's illustrated by Paul O. Zelinsky. There's also a surprisingly subversive ending, though with a character like Earwig it should be expected. She's a match for Neil Gaiman's Coraline and the no-nonsense Victoria from Claire Legrand's The Cavendish Home for Boys and Girls. Any of these horror books would make a great addition to an October spooky story month.