Preheat oven to 350 degrees. Spray donut pan with pan release. Place apple cider in small pot over medium low heat and reduce to ¾ cup.
Cream together butter and both sugars in mixer fitted with paddle attachment. Mix on medium-high speed for 3 minutes.
Add in eggs one at a time.
Combine all dry ingredients in one bowl and all wet ingredients in another bowl. Add dry ingredients in three batches, alternating with the wet. Mix until just combined.
Pipe batter into a sprayed donut pan, filling about 2/3 of the way, and bake for 10 minutes. Remove from hot pan immediately and place onto cooling rack. Continue the process until all batter has been used, about 18 donuts.
Once baked, dip each side of the donut in apple cider. Do not submerge the whole donut. Let donut sit for one minute then coat in cinnamon sugar. Keep in an airtight container for 5 days or freeze up to one month.