Preheat the oven to 325 degrees F & line cupcake pans with cupcake liners.
Add the dry ingredients to a mixing bowl (flour, sugar, cake mix) and whisk to blend.
Next add the eggs, sour cream, melted butter, milk, and vanilla (everything but the apples)
Mix on low speed for 10 seconds to begin incorporating the ingredients and then bump up the speed to medium, mixing for 2 minutes.
Gently stir in the diced apples.
Fill the lined cupcake pans with batter- about ¼ cup of batter per cupcake.
Bake at 325F for 16-18 minutes or until an inserted toothpick comes out clean or with just a few moist crumbs attached.
This recipe makes approximately 28-30 cupcakes.