Bring to boil over medium-high heat and then cook until it becomes reduced to 1/4 cup, about 10 minutes.
Preheat the oven to 350*F.
Coat the donut pan with non-sticking cooking spray.
In a large bowl, beat sugar and butter until well combined.
Add the eggs and mix well.
Add buttermilk and reduced apple cider and mix until well combined.
In a medium bowl, whisk together flour, baking powder, baking soda, and spices.
Add dry ingredients to wet ingredients and stir just until combined.
Fill donut pan about 1/2 full - see notes.
Bake for 10-12 minutes or until lightly browned.
Cool on a wire rack for 5 minutes.
Remove from pan.
Combine the cinnamon and sugar if you are doing the Cinnamon Sugar Coating
If using the glaze, be sure to see the note below.
Melt butter in a microwave-safe bowl and cool slightly.
Dip donuts in the cooled butter and immediately coat both sides with the cinnamon-sugar mixture and set on a wire rack.
Serve warm or room temperature.
Store leftovers in an airtight container.
Donut Pan - To make filling the pan easier, use a plastic decorator bag or resealable bag.Glaze - Add powdered sugar to a medium bowl, add the milk and juice and whisk until smooth. Add additional liquid if the glaze is too thick. Dip donuts top side down into glaze and place on a wire rack to cool and drip off excess.