Do you know this 80s/90s kids book?

Someone help. I'm trying to find a book from my childhood in the late 80s or early 90s but I can't remember the name and it's driving me mad. The book had a hard white cover and was a story about a family preparing for a Halloween party. It centred around a brown dog who dipped his ear in treacle in the story. I would so love to find this book if anyone has any ideas what it may be I'd be really greatful.