• Preheat your oven to 350°F and position the oven rack in the middle. Generously coat a bundt pan with non-stick spray, ensuring all surfaces are covered to prevent sticking.
• In a medium saucepan, combine the chopped apple and apple cider, bringing them to a boil over medium-high heat. Once boiling, lower the heat to medium and allow the mixture to simmer for 10 to 12 minutes, or until most of the cider has reduced and the apples can be easily mashed with a fork. Take the pan off the heat, let it cool for about 5 minutes, and then mash the mixture using the back of a spoon. Measure out 1 cup of the mashed apple mixture, stir in the milk, and set it aside.
• In a separate medium bowl, whisk together the flour, baking powder, baking soda, salt, nutmeg, and mace. Set this dry mixture aside for later use.
• In a large mixing bowl, use an electric mixer on medium speed to cream the butter, granulated sugar, and brown sugar together until the mixture becomes light and fluffy, which should take about 3 minutes. Add the eggs one at a time, making sure to beat well after each addition. Pour in the oil and mix until it's fully incorporated, which should take around 1 minute.
• Lower the mixer speed to the slowest setting, and gradually incorporate the dry ingredients in three batches. Alternate between adding the flour mixture and the apple mixture, beginning and ending with the dry ingredients. Scrape down the sides of the bowl as needed to ensure everything is well combined. Once all the ingredients are added, increase the mixer speed to medium and beat the mixture just until everything is well combined, about 20 seconds. Stir in the vanilla extract, giving it one final mix for about 10 seconds to combine.
• Pour the batter evenly into the prepared bundt pan, smoothing the top if necessary. Bake for 35 to 45 minutes, rotating the pan halfway through the baking time. The cake is done when a toothpick or cake tester inserted into the thickest part comes out clean.
• Once the cake is baked, let it cool in the pan for 10 minutes, then invert it onto a cooling rack placed over a baking sheet to catch any excess sugar coating.

For the Cinnamon Sugar Coating:

• In a small bowl, combine the sugar, cinnamon, nutmeg, and salt. While the cake is still warm, sprinkle this mixture over the cake, using your hands to gently press the cinnamon sugar onto the sides to ensure even coverage.