01 - Preheat oven to 350°F. Grease and flour a 10-cup bundt pan thoroughly.
02 - Simmer apple cider in a saucepan over medium heat until reduced to 3/4 cup, about 15 minutes. Set aside to cool.
03 - Whisk together flour, baking powder, baking soda, salt, cinnamon, nutmeg, allspice, and cloves in a medium bowl.
04 - Beat unsalted butter, granulated sugar, and brown sugar in a large bowl until light and fluffy, approximately 3 to 4 minutes.
05 - Add eggs one at a time, mixing well after each addition. Stir in sour cream and vanilla extract.
06 - Add dry ingredients in three parts, alternating with the cooled reduced apple cider, beginning and ending with the flour mixture. Mix until just combined.
07 - Gently fold the diced apples into the batter until evenly distributed.
08 - Pour batter evenly into the prepared bundt pan and smooth the top. Bake for 45 to 55 minutes or until a toothpick inserted in the center emerges clean.
09 - Let the cake cool in the pan for 15 minutes, then invert onto a wire rack to cool completely.
10 - Whisk powdered sugar with apple cider until smooth and pourable. Drizzle over the cooled cake before serving.