<P> A peanut butter cookie is a type of cookie that is distinguished for having peanut butter as a principal ingredient . The cookie generally originated in the United States, its development dating back to the 1910s . </P> <P> George Washington Carver (1864 - 1943), an American agricultural extension educator, from Alabama's Tuskegee Institute, was the most well known promoter of the peanut as a replacement for the cotton crop, which had been heavily damaged by the boll weevil . He compiled 105 peanut recipes from various cookbooks, agricultural bulletins and other sources . In his 1916 Research Bulletin called How to Grow the Peanut and 105 Ways of Preparing it for Human Consumption, he included three recipes for peanut cookies calling for crushed / chopped peanuts as an ingredient . It was not until the early 1920s that peanut butter was listed as an ingredient in the cookies . </P> <P> The early peanut butter cookies were rolled thin and cut into shapes . They were also dropped and made into balls . They did not have fork marks . The first reference to the famous criss - cross marks created with fork tines was published in the Schenectady Gazette on July 1, 1932 . The Peanut Butter Cookies recipe said "Shape into balls and after placing them on the cookie sheet, press each one down with a fork, first one way and then the other, so they look like squares on waffles ." Pillsbury, one of the large flour producers, popularized the use of the fork in the 1930s . The Peanut Butter Balls recipe in the 1933 edition of Pillsbury's Balanced Recipes instructed the cook to press the cookies using fork tines . The 1932 or 1933 recipes do not explain why this advice is given, though: peanut butter cookie dough is dense, and without being pressed, it will not cook evenly . Using a fork to press the dough is a convenience; bakers can also use a cookie shovel . </P>

Why do you put fork marks on peanut butter cookies