Preheat the air fryer to 350°F (175°C) for 3–5 minutes. Lightly grease the basket to prevent sticking.

Prep the apples. Wash and dry. Use an apple corer or a small paring knife to remove the core, stopping about 1/2 inch from the bottom to keep a base. Widen the cavity slightly to make room for filling. Brush the insides with lemon juice.

Mix the filling. In a bowl, combine oats, brown sugar, cinnamon, nutmeg, and salt. Stir in melted butter and vanilla until the mixture looks like damp sand. Fold in nuts and dried fruit if using.

Stuff the apples. Pack the filling firmly into each cavity, mounding a little on top for a crisp crown.

Arrange in the basket. Place apples upright in the air fryer, leaving space between them for airflow. If they wobble, trim a thin slice from the bottom to level.

Air fry for 12–15 minutes. Start checking at 10 minutes. The apples are done when a knife slides in easily and the tops look golden and bubbly. If the tops brown too fast, tent each apple loosely with a small square of foil and continue cooking.

Rest for 3–5 minutes. They’ll be hot and juicy. Resting helps the juices settle so the apples hold their shape.

Serve warm. Add a scoop of ice cream, a dollop of yogurt, or a drizzle of caramel or maple syrup. Sprinkle extra cinnamon if you like.