Preheat oven to 350 degrees and grease your donut pan.
In a saucepan over medium heat, heat the apple cider until it begins to simmer.
Continue simmering (and stirring) for about 10 minutes, or until liquid has been reduced by about half.
Remove from heat and stir in the butter until melted. Set aside to cool slightly.
In a medium bowl, combine 1/2 cup of the cider mixture with the sugar, egg, yogurt, and vanilla extract.
In a separate medium bowl, combine the flour, cinnamon, nutmeg, cloves, salt, baking powder, and baking soda.
Combine the dry ingredient mixture with the cider/egg/yogurt mixture and stir until just combined.
Pipe the batter into the donut cavities evenly. (you can pour batter into a Ziploc bag, cut the corner of the bag off, and pipe the batter in that way)
Place donut pan into preheated oven and bake for about 10 minutes.
Remove from oven and allow to cool for a few minutes before removing from pan.
To prepare topping: combine 2 tbsp of the apple cider reduction with the melted butter and place in container large enough to dip donuts into.
In a separate bowl, combine the cinnamon/sugar.
To coat donuts, dip one side into the butter mixture and immediately dip into the cinnamon/sugar mixture.
Set onto a cooling rack or serve immediately! Enjoy!