Step 1: Make the Apple Cider Reduction
Pour the 1 ½ cups of apple cider into a small saucepan. Bring to a boil over medium-high heat, then reduce the heat to maintain a steady simmer. Let the cider simmer, uncovered, for about 15-20 minutes, or until it has reduced in volume to approximately ½ cup. It will be slightly thicker and more syrupy. Set it aside to cool down while you prepare the rest of the ingredients. This step is crucial and cannot be skipped.

Step 2: Preheat and Prepare Your Pan
Preheat your oven to 350°F (175°C). Generously grease a standard 6-cavity or 12-cavity donut pan with non-stick baking spray or softened butter. Even if your pan is non-stick, this step is vital to ensure the donuts release cleanly. Use a paper towel to make sure every part of the cavities, including the center spindle, is coated.

Step 3: Combine the Dry Ingredients
In a large bowl, whisk together the all-purpose flour, baking powder, baking soda, ground cinnamon, nutmeg, allspice, and salt. Whisking thoroughly not only combines the ingredients but also aerates the flour, much like sifting.

Step 4: Combine the Wet Ingredients
In a separate medium bowl, whisk the two large eggs until they are pale and slightly frothy. Whisk in the packed light brown sugar until it is fully incorporated. Then, whisk in the buttermilk, the melted butter, and the cooled apple cider reduction until the mixture is smooth.

Step 5: Mix the Batter
Pour the wet ingredients into the bowl containing the dry ingredients. Use a rubber spatula to gently fold the ingredients together until they are just combined. It’s very important not to overmix! A few small lumps in the batter are perfectly fine. Overmixing develops the gluten in the flour and will result in tough, dense donuts instead of light, tender ones.

Step 6: Fill the Donut Pan
This step can be messy if done with a spoon. For perfectly shaped donuts and easy filling, transfer the batter to a large piping bag or a large zip-top plastic bag. Snip off a corner of the bag (about a ½-inch opening). Carefully pipe the batter into each cavity of the prepared donut pan, filling them about ¾ of the way full. Do not overfill them, as they will rise during baking.

Step 7: Bake to Golden Perfection
Place the donut pan in the preheated oven and bake for 12-15 minutes. The donuts are done when they are golden brown and a wooden skewer or toothpick inserted into the center of a donut comes out clean with no wet batter attached. The tops should also spring back lightly when touched.

Step 8: Cool and Coat
Let the donuts cool in the pan for 5 minutes. This allows them to set up slightly so they won’t break when you remove them. After 5 minutes, carefully invert the pan onto a wire cooling rack. The donuts should fall right out.

While the donuts are still warm, prepare the topping. In a shallow bowl, place the ½ cup of melted butter. In a separate shallow bowl, whisk together the granulated sugar and the 1 ½ teaspoons of cinnamon.

Working one at a time, dip the entire warm donut into the melted butter, ensuring it’s fully coated. Let any excess butter drip off, then immediately transfer the donut to the cinnamon-sugar mixture. Toss it gently to coat all sides generously. Place the finished donut back on the wire rack. Repeat with the remaining donuts.