Preheat the oven to 350°F. Lightly grease one or two 6-count donut pans.
Combine ground flaxseed and warm water and set aside for 10 minutes.
Beat together the oil, flax-water mixture, sugar, pumpkin, milk, spices, salt, baking powder and baking soda until smooth.
Add the flour, stirring just until smooth.
Fill the wells of the donut pans about ¾ full; use a ¼ cup of batter in each well.
If the batter doesn't smooth out, add a little more milk. Bake the donuts for 15 to 18 minutes, or until a cake tester inserted into the center of one comes out clean.
Remove the donuts from the oven, and after about 3 minutes, loosen their edges and transfer them to a rack to cool. (If you only have one pan, repeat with rest of batter.)
While the donuts are still warm (but no longer fragile), gently shake them in a bag with the cinnamon-sugar.
If there are any left, cool completely and wrap airtight; store at room temperature for several days.
Recipe by forkbelly.com at http://forkbelly.com/vegan-pumpkin-cake-donuts/