Preheat your air fryer to 375°F (190°C).
In a bowl, mix the brown sugar, melted butter, cinnamon, and vanilla extract.
Brush the pineapple slices with the sugar mixture.
Place the slices in the air fryer basket in a single layer.
Cook for 8-10 minutes, flipping halfway through, until caramelized.
Serve warm and enjoy!