01 - In a small saucepan, simmer 1 cup of apple cider over medium heat until it reduces to 1/2 cup. Let it cool completely before proceeding.
02 - Preheat your oven to 350°F (175°C). Line a standard 9x5 inch loaf pan with parchment paper, leaving an overhang on the sides for easy removal.
03 - In a large bowl, whisk together the all-purpose flour, granulated sugar, brown sugar, baking powder, ground cinnamon, ground nutmeg, and salt. In a separate medium bowl, whisk together the eggs, neutral oil, sour cream, and the cooled reduced apple cider until well combined. Pour the wet ingredients into the dry ingredients and mix until just incorporated. Be careful not to overmix.
04 - Pour the batter into the prepared loaf pan and spread evenly. Bake for 45 to 55 minutes, or until a wooden skewer inserted into the center comes out clean.
05 - While the loaf is still warm, brush the melted butter evenly over the top. Immediately sprinkle the cinnamon-sugar mixture over the buttered surface, ensuring it's well coated. Allow the loaf to cool in the pan for 20 minutes before carefully removing it using the parchment paper overhang.