1. Start by preheating your air fryer to 350°F. This ensures the apples cook evenly and develop that beautiful caramelization.
2. While the air fryer is heating, peel and core the apples. Slice them into 1/4-inch thick pieces. I always remember my mom using an old-fashioned apple peeler, which made the task almost meditative.
3. In a large bowl, combine the melted butter, brown sugar, cinnamon, nutmeg, vanilla extract, and a pinch of salt. Stir until everything is well incorporated.
4. Add the sliced apples to the bowl and toss until they are fully coated with the cinnamon-sugar mixture.
5. Arrange the apple slices in a single layer in the air fryer basket. You might need to cook them in batches depending on the size of your air fryer.
6. Cook the apples for 10-12 minutes, shaking the basket halfway through to ensure even cooking. They should be tender and slightly caramelized when done.
7. Once cooked, let the apples cool for a few minutes before serving. This allows the flavors to meld beautifully.

Remember, cooking times can vary based on your specific air fryer model, so keep an eye on the apples to prevent overcooking.