- 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.