Grunger,
I can't remember the details, but the Chambers definition of Bandbox gave no reasonable link to the clue!
I think you might have to try DIT for your Pie obsession. This is Deep Immersion Therapy, and it involves you being subjected to a veritable onslaught of pies. Pies on plates, pies in photographs, the word 'pie' being inserted, as often as possible, into messages, letters, posts. This will, in theory, make you recoil at some point- and voila, your obsession will be gone. Let me know how it goes.