Instructions

1. Prepare: Heat the oven to 350 degrees F. Lightly grease two 6-cavity donut pans (or a 12-cup muffin tin) with nonstick spray
2. Make Apple Cider Reduction: In a small saucepan, heat the apple cider over medium heat, stirring occasionally, until it comes to a simmer. Continue to simmer, stirring occasionally, until it is reduced by about half, around 10 minutes. Remove from the heat and set aside. (You will need ½ cup of this apple cider reduction for the donut batter and a few tablespoons for topping the donuts)
3. Make the Donuts: In a medium bowl, add the flour, baking powder, salt, and 1½ teaspoons cinnamon and whisk to combine. Set aside. In the bowl of a stand mixer fitted with the paddle attachment, cream together 10 tablespoons butter, brown sugar and ¼ cup granulated sugar on medium speed until light and fluffy, 3 to 4 minutes. Add the eggs one at a time and mix until well incorporated after each addition, scraping the bowl as necessary. Beat in the vanilla extract and sour cream or yogurt. Add the flour mixture and mix on low speed until incorporated. With the mixer running, add ½ cup of the apple cider reduction in a slow, steady stream and mix to combine. Scrape the bowl well to make sure the batter is evenly mixed. Spoon the batter into prepared donut pans, filling them about ⅔ of the way full (you can also do this using a disposable piping bag or a resealable plastic bag with a ½-inch opening cut from one corner). Bake until evenly golden brown, rotating the pans halfway through baking, 9 to 11 minutes  A toothpick inserted into the center of the thickest portion should come out clean when they are done 
4. Prepare Cinnamon Sugar & Top Donuts: While the donuts cool, whisk the remaining ½ cup granulated sugar and 1 teaspoon cinnamon together in a small bowl to combine. In a separate small bowl, melt the remaining 6 tablespoons of butter in the microwave then whisk in 3 tablespoons of the apple cider reduction. After the donuts have cooled slightly (at least 5 minutes), unmold them from the pans, brush with the melted butter/cider mixture and dredge them in the cinnamon sugar while they are still warm. Serve immediately or allow to cool and warm gently in the oven prior to serving for the best apple cider donut experience!