Just in time for the winter holiday season in the Northern Hemisphere, this food holiday celebrates the ubiquitous cookie. Look for bakeries honoring the day with free cookies, deals, and giveaways. While cookies have been in ovens since at least the 7th century, the concept of a “cookie day” seems to have originated with the Cookie Monster on Sesame Street in the 1970s and then was designated December 4 by the Blue Chip Cookie Company of San Francisco in 1987.