Preheat the oven to 350°F and spray your donut pan.
In a medium bowl, add the dry ingredients (Kodiak Cakes, protein powder, sugar, baking powder, and salt) and whisk together.
In a small bowl, whisk together the milk, pumpkin, egg whites, egg, and syrup. Combine the wet ingredients into the dry ingredients and fold together until smooth. Make sure not to overmix the batter.
Add the donut batter to the pan. You may spoon batter directly into the compartments or use a ziploc bag to pipe the batter into each donut tin.
Bake for 9-11 minutes on the center rack of the oven. Let cool in the pan for 1 minute then transfer to a cooling rack.
To prepare the icing, whisk together the powdered sugar, cinnamon, and water in a small bowl. If you prefer a thinner icing, add more water; if you prefer a thicker icing, add less water.
Holding the bottom of the donut, dip the top into the glaze and place on drying rack. For a more intense cinnamon sugar flavor, sprinkle with Cinnamon Toast Crunch seasoning. Enjoy!