Place 2 cups of apple cider in a small saucepan. Bring to a simmer over medium-low heat and simmer gently for 20-30 minutes until reduced to ½ cup. Set aside to cool to room temperature.

Preheat the oven to 400°F. Thoroughly grease a 24-count mini muffin tin.

Using a hand mixer or stand mixer, beat the applesauce and sugar and egg until combined. Add the baking powder, baking soda, cinnamon, salt, and vanilla, beat to combine. Add half the flour, beat until combined. Add the cider reduction, beat until combined. Add the remaining flour, beat until combined, being careful not to overmix.

Divide the batter between 22 mini muffin cups. I used a cookie scoop and placed a heaping 2 teaspoons of batter into each cup. Bake for 8-10 minutes, until the top springs back when you press it. Place pan on a rack to cool.

If you're making the glaze: whisk the powdered sugar with apple cider until smooth. Dip or spoon the glaze over the donut holes until covered. I dip them into the glaze, roll them around and then remove with a fork and place on a rack for the excess glaze to drip off. Allow to sit at room temperature for an hour or two so the glaze can firm up.

If you're making the cinnamon sugar: Fill a large shallow bowl with cinnamon and sugar, stirring to combine. Lightly brush the donut holes with apple cider and then roll them in the cinnamon sugar. Don't saturate the donut holes with cider, just brush on enough to moisten them so that the cinnamon sugar will stick.