For the coating: 1/2 cup granulated sugar, 1 tablespoon ground cinnamon, 4 tablespoons unsalted butter, melted
Instructions
In a small saucepan over medium-high heat, simmer the apple cider until it has reduced to exactly 1/2 cup. This should take about 10-12 minutes. Set it aside to cool slightly. This step is crucial for achieving that deep, concentrated apple flavor.
Preheat your oven to 350°F (175°C). Lightly grease a 24-count mini-muffin tin with non-stick cooking spray or a little bit of melted butter to ensure the donut holes pop out easily after baking.
In a large mixing bowl, whisk together the all-purpose flour, baking powder, baking soda, 1 1/2 teaspoons of cinnamon, nutmeg, and salt. Ensure there are no large clumps so the batter stays light and airy.
In a separate medium bowl, whisk together the 1/2 cup of sugar, the room temperature egg, the 2 tablespoons of melted butter, and the vanilla extract. Once smooth, whisk in the buttermilk and the cooled, reduced apple cider.
Pour the wet ingredients into the dry ingredients. Use a spatula to gently fold the mixture together until just combined. Be careful not to overmix, as this can make the donut holes tough instead of fluffy.
Spoon the batter into the prepared mini-muffin tin, filling each cup about 3/4 full. Bake for 12 to 15 minutes, or until a toothpick inserted into the center comes out clean. Let them cool in the pan for only 2-3 minutes before moving to the next step.
While the donut holes are still warm, melt the 4 tablespoons of butter in a small bowl. In another bowl, mix the sugar and cinnamon for the coating. Dip each donut hole quickly into the melted butter, then roll it in the cinnamon-sugar mixture until fully coated.