Duck Donuts, the chain with more than 150 locally owned and operated shops across 25 states, Puerto Rico and international locations, is ready to kick off summer with the free classic sweet treat on National Donut Day. Guests are invited to join the party at any Duck Donuts location on Friday, June 7, for one free cinnamon sugar donut per guest, no purchase necessary, in-store only.

National Donut Day, which is traditionally celebrated on the first Friday of June, was established in 1938 by the Chicago Salvation Army to honor women who served donuts, known as “doughnut lassies,” to soldiers during World War I.

Also this month, Duck Donuts has announced that its donuts can be topped with TWIX Cookie Bars. The candy featuring shortbread cookie pieces, smooth caramel and creamy chocolate can now be enjoyed in the recommended Caramel Cookie Dozen, Half Dozen or in build-your-own combinations for a limited time through June 30.

Tasty combinations include:

• Vanilla Caramel Delight topped with TWIX – Vanilla icing with chopped TWIX Cookie Bar and caramel drizzle
• Chocolate Delight topped with TWIX – Chocolate icing with chopped TWIX Cookie Bar