National Oatmeal Cookie Day is celebrated on April 30, primarily in the United States, and is dedicated to enjoying oatmeal cookies. This day highlights the health benefits of oatmeal cookies, which are rich in iron and fiber, allowing people to indulge without guilt. In addition to the April celebration, some also observe National Lacy Oatmeal Cookie Day on March 18. The origins of oatmeal cookies date back to the 1800s, with Fannie Merritt Farmer credited for creating the first oatmeal cookie in the U.S. Their popularity surged in the 1900s when the Quaker Oats Company printed the recipe on their containers. Overall, this day encourages people to appreciate and enjoy the deliciousness of oatmeal cookies.