Prepare Pan & Oven:
Preheat oven to 350°F (175°C) and position rack in the center. Generously spray a 10–12 cup Bundt pan with baking spray that includes flour, making sure to coat all crevices.

Mix Dry Ingredients:
In a medium bowl, sift together cake flour, baking powder, cinnamon, nutmeg, and ginger. Set aside.

Cream Butter & Sugars:
In a large bowl, beat butter using an electric mixer on medium speed until fluffy (about 2 minutes). Add white sugar and brown sugar, then continue creaming for 3–4 minutes until light and airy.

Add Eggs & Vanilla:
Beat in the eggs one at a time, mixing after each addition. Add vanilla extract and mix until smooth.

Combine Wet Ingredients:
In a separate bowl, whisk together sour cream and apple cider until smooth.

Combine Mixtures:
Gently fold one-third of the dry mixture into the butter mixture. Add half of the sour cream mixture, then repeat with another third of dry ingredients and the remaining sour cream mixture. Finish with the last third of the dry ingredients, folding gently to avoid overmixing.

Add Apples:
Fold in the grated apples until evenly distributed.

Bake:
Pour the batter into the prepared Bundt pan, smoothing the top. Bake for 55–65 minutes, or until a toothpick inserted in the center comes out clean.

Cool:
Let the cake cool in the pan for 10 minutes, then invert onto a wire rack to cool completely.

Make the Topping:
In a small bowl, mix together sugar, cinnamon, and nutmeg (if using). Brush melted butter over the cooled cake, then sprinkle or press the cinnamon-sugar mixture evenly over the surface.

Serve:
Slice and serve at room temperature — enjoy that perfect apple cider donut flavor in cake form!