Pour the apple cider into a small saucepan and heat until reduced to ½ cup.
Preheat the oven to 350 degrees F.
In a medium mixing bowl add the flour, baking powder, baking soda, salt, and apple pie spice, whisking to combine.
In a medium bowl stir together the reduced cider, milk, and vanilla.
In the bowl of a stand mixer fitted with a paddle attachment, combine the sugar and
butter and mix until creamed, 4-5 minutes, scraping down the bowl as needed.
Continue to mix adding the eggs one at a time until incorporated.
With the mixer on low, add 1/3 of the flour mixture, then ½ of the liquid. Continue to alternate between the flour and the liquid until all the ingredients are in the
bowl, end with the flour mixture. Continue mixing until the batter is just combined.
Using a spatula, fold the batter over in the bowl 2-3 times to ensure it is mixed together.
Transfer the batter to a piping bag with a small to medium size piping tip. You can also put the batter into a large zip-close bag and cut off a corner, being careful
not to make too large a cut. You can always cut a little more; you can’t make
the hole small once you have cut it!
Pipe the batter into the donut molds filling 2/3 full.
Bake the donuts until they spring back and a toothpick inserted into the middle comes out clean, 20-25 minutes.
Turn the donuts out onto a cooling rack and allow to cool. You can store the donuts in an airtight container for 3-4 days on your counter.
Mix the sugar and apple pie spice together in a small bowl.
Butter the outsides with the melted butter and roll the donuts in the sugar apple spice mixture before serving. If you leave the donuts for a day in an airtight container you won't need to butter before rolling.