Reduce the cider to about 1/2 cup over medium heat, then cool slightly.
Heat oven to 350°F. Grease two 6-cavity donut pans.
Whisk flour, baking powder, baking soda, salt, cinnamon, nutmeg, and cloves in a bowl.
Whisk melted butter with granulated and brown sugars until sandy and combined.
Whisk in beaten eggs, vanilla, buttermilk, and the reduced cider until smooth.
Fold dry ingredients into the wet mixture until just combined; do not overmix.
Pipe or spoon batter into pans, filling each cavity about three-quarters full.
Bake 11–13 minutes until tops spring back; rotate pans halfway through.
Cool 5 minutes, then turn donuts onto a rack to finish cooling.
Mix coating sugar and cinnamon. Brush donuts with melted butter and toss in cinnamon sugar.