Preheat the oven to 325°F . Grease a 10-inch Bundt pan with oil.
Sift together coconut flour, almond flour, oat flour, baking powder, apple pie spice, salt, arrowroot powder, and xanthan gum in a large mixing bowl. Whisk to combine.
In a separate bowl, using your KitchenAid mixer with the paddle attachment, cream together the granular sweetener and coconut oil until well combined and smooth. Add the vanilla extract, then beat in the eggs one at a time. After all the eggs have been added, continue to beat at high speed for 3 minutes until the mixture is creamy and light.
Lower the speed and gradually mix in the applesauce until it is thoroughly combined with the other wet ingredients.
Slowly add the dry ingredients to the wet mixture, stirring just until combined and no dry streaks are visible. Avoid over-mixing.
Gently fold the chopped apples into the batter, ensuring they are evenly distributed.
Pour the batter into the prepared Bundt pan, smoothing the top with a spatula.
Bake the cake for approximately 1 hour and 10 minutes. At the 55-minute mark, begin to check for browning. If necessary, lightly tent the cake with aluminum foil to prevent the top from over-browning. Continue baking until a toothpick inserted into the center comes out clean.
Once baked, remove the cake from the oven. Let it cool in the Bundt pan for 30 minutes, then invert the cake onto a wire rack to cool completely, which will take about an additional hour. The cake must be cool to the touch before you slice it.
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Notes
Please note that the nutrition data given here is a ballpark figure. Exact data is not possible.