Preheat your oven to 350°F (175°C).

Peel, core, and finely dice 2 to 3 Granny Smith apples.

In a large mixing bowl, combine the yellow cake mix with the ingredients specified on the package and beat until smooth.

Stir in 1 to 2 teaspoons of cinnamon powder and 1 teaspoon of vanilla extract.

Gently fold the diced apples into the batter using a spatula.

Grease a 10-inch tube pan and pour the apple cake batter into it, smoothing the top.

Bake for approximately 40 minutes or until a toothpick inserted in the center comes out clean.

Once baked, cool in the pan for about 15 minutes before inverting onto a wire rack.