Beginning in 1917, approximately 250 Salvation Army volunteers provided assistance during World War I to American soldiers in battle on the front lines in France.

Two female Salvation Army officers, Ensign Margaret Sheldon and Adjutant Helen Purviance had an idea to comfort our soldiers with good home cooking, using their limited ingredients to fry up in helmets delicious doughnuts for the boys.

Nicknamed “Doughnut Lassies” and “Doughnut Girls”, these women served countless treats to grateful soldiers, traversing through the trenches to bring the men doughnuts and coffee. They also made history by introducing this tasty new treat to the United States when the “Doughboys” returned from war.
 

The Salvation Army celebrated the first National Doughnut Day in 1938 in the city of Chicago as a way to honor Salvation Army “doughnut lassies” from World War I. They began the holiday as a way to raise funds and bring awareness to the Army’s social service programs during the Great Depression.The donut has become synonymous with The Salvation Army’s social services and continues to be a comfort food served by The Salvation Army to those in need during times of disaster.

Above Information from https://blog.salvationarmyusa.org/nhqblog/news/the-salvation-army-celebrates-national-donut-day