In a small saucepan, bring 1.5 cups of fresh apple cider to a gentle boil over medium heat. Simmer for 15 to 20 minutes until reduced down to exactly 1/2 cup of concentrated cider syrup. Set aside to cool to room temperature. This is the ultimate pro secret for intense real apple flavor without making the batter runny!

Preheat oven to 350°F (175°C). Generously grease two 6-cavity standard donut pans with nonstick baking spray.

In a large bowl, whisk together flour, baking powder, baking soda, ground cinnamon, nutmeg, and salt. In a medium bowl, whisk together melted butter, brown sugar, white sugar, egg, buttermilk, vanilla extract, and the cooled reduced apple cider until smooth.

Pour wet ingredients into dry ingredients. Fold gently with a spatula just until combined—do not overmix. Transfer batter to a gallon zip-top bag or piping bag, snip the corner, and pipe evenly into the greased donut pan cavities, filling each about 3/4 full.

Bake at 350°F for 10 to 12 minutes until donuts spring back lightly when pressed and a toothpick inserted into the center comes out clean. Let cool in the pan for 5 minutes, then invert onto a wire rack.

In a shallow bowl, whisk granulated sugar, ground cinnamon, and apple pie spice. Melt 6 tablespoons of butter in a separate bowl. While donuts are still warm, brush both sides generously with melted butter, then dredge thoroughly in the cinnamon sugar coating until thickly crusted. Serve warm!