01 - Preheat your oven to 375°F (190°C). Line a baking sheet with parchment paper for easy cleanup.
02 - Wash and core the apples. Slice them into uniform 1/4-inch thick rings. Lightly pat the apple slices dry with a paper towel to help the coating adhere.
03 - In a shallow bowl, combine the granulated sugar and ground cinnamon. Stir until thoroughly mixed.
04 - Using a pastry brush, lightly coat both sides of each apple ring with melted unsalted butter.
05 - Dredge each buttered apple ring in the prepared cinnamon sugar mixture, ensuring an even coating on all sides.
06 - Place the coated apple rings on the prepared baking sheet in a single, even layer. Avoid overcrowding.
07 - Bake for 18 to 22 minutes. Midway through cooking, gently flip the apple rings to ensure even caramelization. The apples should be tender and the sugar beautifully caramelized.
08 - Remove the baking sheet from the oven and allow the apple rings to cool for approximately 5 minutes. Carefully transfer them to a serving plate.
09 - If desired, dust the apple rings with powdered sugar or drizzle with caramel sauce. Serve warm or at room temperature.