Simmer apple cider over low-medium heat in a small saucepan on the stove for 15-20 minutes. Add cinnamon sticks, cloves, spices, and/or orange slices for flavor if desired. In this step you are reducing the apple cider for a stronger flavor. You will need ½ cup from this reduced cider. Allow it to cool in the refrigerator as you prepare the other ingredients.
Preheat oven to 350F degrees. Spray a donut pan with nonstick spray. Set aside.
Toss the flour, baking powder, baking soda, cinnamon, cloves, and salt together in a large bowl. Set aside. In a medium bowl, whisk the egg, melted butter, brown sugar, and granulated sugar together until smooth. Whisk in the buttermilk, vanilla, and ½ cup of concentrated apple cider.
Pour the wet ingredients into the dry ingredients and very gently mix together with a whisk. Be very gentle as over-mixing will develop the gluten and result in a tough textured donut. Whisk until all ingredients are *just combined.* Some small lumps may remain, but not many.
To fill the donut pan up with batter, simple spoon the batter into a large zipped-top bag, cut off one bottom corner and pipe the batter into the pan. Fill each crevice ⅔ of the way full. (Any more than that and the donuts will puff up and you will lose the hole in the center.) Bake the donuts for 9-10 minutes or until a toothpick inserted in the center comes out clean. The donuts will take the same amount of time.
Mix sugar, brown sugar and cinnamon in a small bowl. Brush each donut with the melted butter and toss it in the sugar mixture.
Recipe by Culinary Mamas at https://culinarymamas.com/baked-apple-cider-donuts/