Preheat the oven to 400 degrees. Spray the (6) cavities of a donut pan with cooking spray and set aside.
In a medium bowl, whisk together the flour, baking powder, baking soda, spices, and salt. Set aside.
In a medium bowl, whisk together the egg, oil, and sugar vigorously until frothy, about 1 minute. Whisk in the pumpkin, milk, Greek yogurt, and vanilla until well combined.
Stir the wet ingredients into the dry ingredients just until combined, and divide evenly among the (6) cavities in the donut pan. I found it's easiest to place the batter in a ziplock bag, snip off a corner, and pipe it in. Bake for 10-12 minutes or until the tops spring back when pressed gently or a toothpick inserted into the center comes out clean. Cool for 10 minutes in the pan, then remove from the pan and transfer to a wire rack and cool completely.
Prepare the glaze:
Place a sheet of waxed paper underneath the wire rack. Place the powdered sugar, milk, and coffee into a small bowl and whisk together vigorously until smooth. If you like a thicker glaze, add a couple tablespoons more powdered sugar. Dip the top of each donut into the glaze, and place on the wire rack. Repeat with the remaining donuts and let stand at room temperature until the glaze has set. Serve and enjoy!
Notes
To make these donuts whole grain, use 2/3 cup all purpose and 1/3 cup whole wheat flour.
The Greek yogurt may be substituted with sour cream.
Instant espresso powder may be used for the glaze -- simply follow the instructions on the back of the label.