Prep Apples: Wash the apples and slice them in half. Use a spoon or apple corer to remove the core and seeds from the center of each half.
Make Filling: In a small bowl, mix melted butter, brown sugar, cinnamon, rolled oats, and chopped nuts until combined.
Fill & Air Fry: Spoon the cinnamon oat mixture evenly into the hollowed centers of the apple halves. Place them in the air fryer basket.
Cook: Air fry at 350°F (175°C) for 7–8 minutes until the apples are tender and the topping is golden and crispy.
Serve: Serve warm as is, or top with a scoop of vanilla ice cream and a drizzle of caramel syrup. Enjoy!