In a large pan, heat the oil to 375 degrees.
Sift all of the dry ingredients into a bowl and whisk together. Make a well in the center. In another bowl, mix the apple cider reductions and the sour cream. If it is still hotter than body temp, cool it over an ice bath. When cooled, add the eggs and vanilla, and whisk to break up the eggs.
Place the yeast in the well of the flour. Pour the liquid over the yeast and mix together with your hand until just combined. Heavily flour a work surface. Using a bowl scraper, remove the dough from the bowl and place onto the floured surface. Flour your hands and pat the dough down until it is ½-inch thick. Use a donut cutter or a 3 ½-inch cutter for the donut and 1 inch cutter for the middle to cut out the donut.
Fry immediately, working fast so that the leaveners do not cause the dough to rise. Fry until golden on each side. Dredge the donuts in the cinnamon sugar before serving.