01 - Peel the bananas and slice them into thin, even rounds approximately 1/8 inch thick. A mandoline slicer works well for consistent thickness.
02 - Combine granulated sugar and ground cinnamon in a small bowl, stirring until evenly blended.
03 - Lightly brush both sides of each banana slice with melted coconut oil using a pastry brush, then sprinkle the cinnamon sugar mixture evenly over both sides.
04 - Place the coated banana slices in a single layer in the air fryer basket, ensuring pieces do not overlap. Cook in batches if needed. Air fry at 350°F for 10 to 15 minutes, flipping halfway through.
05 - Transfer the banana chips to a wire rack and let cool completely—they will crisp up as they cool. Optionally finish with a light sprinkle of sea salt before serving.