Preheat oven to 325 degrees F and grease and flour a bundt pan.
Peel apples and slice into small pieces. You will need 2 cups. (For us, this was 2 large granny smith apples).Set aside.
In a separate bowl whisk the all purpose flour, baking powder, apple spice, and salt to combine, set aside for later.
Mix the butter on medium speed until smooth (using paddle attachment if you have a stand mixer). Gradually add the white and brown sugar and mix on medium speed until light and fluffy (3 to 5 minutes).
Add the eggs one at a time, blending after each to incorporate.
In a small bowl or measuring cup, combine the sour cream and vanilla extract.
While mixing on low speed, add the flour mixture alternately with the sour cream mixture to the butter, sugar, & egg mixture. Begin and end with the dry ingredients. (I add the flour mixture three times and the sour cream mixture twice). Mix just until incorporated.
Fold in the two cups of diced apples. Scoop into prepared bundt pan.
Bake at 325 degrees for 1 hour, 10-15 minutes. Check on the cake as it nears the 1 hour mark and adjust additional time as needed. When an inserted toothpick or skewer comes out clean or with just a few moist crumbs attached, it is ready.
This recipe makes approximately 8-8.5 cups of batter.