Interestingly, did you know that the English word "cookie" is derived from the Dutch word "koekje," which means "little cake"? Dutch bakers used to test oven temperatures on small amounts of batter so that the entire cake mix would not be wasted if the temperature wasn't right. It wasn't long before they discovered that these miniature test cakes were actually quite tasty!
According to Muppet Wiki, National Cookie Day is a minor holiday, celebrating cookies in all their sugary glory. It occurs on December 4th of every year, but is not widely observed.
Cookie Monster proclaimed his own National Cookie Day in the 1980 book The Sesame Street Dictionary.
National Cookie Day was established in 1987 by one of the founders of San Francisco-based Blue Chip Cookie Company, an American gourmet cookie bakery chain. Now Cookie Day is celebrated around the world, sometimes as Bake Cookie Day and Oatmeal Cookie Day.
Each country has its own word for cookie. What we know as cookies in America are called “biscuits” in England and Australia, “galletas” in Spain, “keks” or “Plätzchen” (Christmas cookies) in Germany and “amaretti” or “biscotti” (among others) in Italy.
Nestle's Infographic - The Most Popular Cookies by State
And just because it's National Cookie Day
HAPPY NATIONAL COOKIE DAY, PALLIES!