Gregg Wallace travels to Oldham to visit the Park Cakes Factory and learn how Marks and Spencer's Snowflake Bauble Christmas Cake is made. Meanwhile, Cherry Healey travels to Langport to learn how glass baubles are made and attempt to make one of her own. Also, Ruth Goodman investigates why fairy lights are used to decorate Christmas trees and explores the inspiration behind Charles Dickens' novel "A Christmas Carol".