Begin by pouring 1 cup of apple cider into a small saucepan. Heat it over medium heat until it reaches a simmer, then reduce the heat and let it gently bubble for about 15–20 minutes, until the cider reduces to around ½ cup. Once reduced, remove it from the heat and allow it to cool slightly.

In a large mixing bowl, whisk together the ½ cup of melted unsalted butter, both the granulated and brown sugars, 2 large eggs, ½ cup of sour cream, 1 teaspoon of vanilla extract, and the cooled apple cider. Blend these ingredients until the mixture is smooth and well combined.

In a separate bowl, combine 2 cups of all-purpose flour, 1 tablespoon of baking powder, ½ teaspoon of baking soda, 1 teaspoon of ground cinnamon, ¼ teaspoon of ground nutmeg, and ½ teaspoon of salt. Whisk these dry ingredients together until they're evenly mixed.

Pour the dry ingredients into the bowl with the wet mixture. Using a spatula or wooden spoon, gently stir the batter until just combined, being careful not to overmix.

Grease a 9×5-inch loaf pan with butter or non-stick spray. Once greased, pour the prepared batter into the pan, smoothing the top with a spatula.

Preheat your oven to 350°F (175°C). Place the loaf pan in the center of the oven and bake for 45–50 minutes. Keep a close eye on the bread towards the end of baking.

Once baked, remove the loaf from the oven and let it cool in the pan for about 10 minutes. After cooling slightly, carefully transfer the bread onto a wire rack to cool completely.

While the bread is still warm, brush the top and sides with melted butter. In a small bowl, combine ¼ cup of granulated sugar and 1 teaspoon of ground cinnamon together. Sprinkle this mixture generously over the bread.