In a small saucepan over medium low heat, simmer the apple cider until you are left with about 1/2 cup of cider, about 45 minutes, stirring occasionally. Set aside to cool, about 10 minutes.
Preheat the oven to 350 degrees. Grease a donut pan with nonstick spray, set aside.
In a large mixing bowl, whisk together the flour, baking soda, baking powder, cinnamon, apple pie spice, and salt.
In a medium bowl, whisk together apple cider, melted butter, egg, brown sugar, granulated sugar, milk, and vanilla extract. Pour cider mixture into the flour mixture. Whisk until smooth.
Spoon batter into donut pan, filling each one about 1/2 way, about 1/4 cup. Bake the donuts until lightly brown on top, about 12 minutes. If donuts bounce back to the touch, then they are done. Remove donuts from pan and cool on a wire rack.
For the topping, in a medium bowl combine the granulated sugar, cinnamon, and apple pie spice. Place the melted butter in a separate medium bowl.
To coat the donuts, working one donut at a time, dip the donuts into the melted butter then gently roll the donut around in the sugar mixture. Serve immediately or can be stored in refrigerator for 5 days in an airtight container.