In a large bowl, add brown sugar and eggs. Whisk to combine.
Slowly whisk in flour, baking powder, vanilla extract, and cinnamon until combined. Your batter should be smooth and creamy.
Fold your chopped apples into the batter until evenly distributed.
Coat your cake pan with cooking spray and pour the batter into it. Give your pan a few taps to eliminate air bubbles and settle your batter evenly.
Place the cake pan directly into the air fryer basket and air fry for 15 minutes at 320F.
Remove your cake from the air fryer. It should have a golden-brown crust. Let it cool for 5 minutes, then give it a dusting of icing sugar if you want.
Serve and enjoy :)
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Notes
Sift your dry ingredients into your mixing bowl to remove any lumps and to ensure even distribution. This will also give you a lighter, fluffier cake.
Fill the pan about two-thirds full with the cake batter to allow room for the cake to rise.
Preheat the air fryer before adding the cake to ensure even cooking and a better rise.
Use a toothpick or cake tester to check if the cake is fully baked. Insert it into the center of the cake; if it comes out clean or with just a few crumbs, the cake is done. If the cake is not done, air fry it for another 3-5 minutes, depending on its state of doneness.