Preheat the oven to 375°F (190°C) and lightly spray your baking dish with non-stick spray to prevent sticking.
Arrange the sliced apples evenly in the prepared baking dish as the first layer, creating a colorful base.
Drizzle the melted butter over the apples, then sprinkle with brown sugar and cinnamon to coat them evenly and bring out their sweetness.
Place the cinnamon rolls on top of the apple layer, arranging them closely together so they touch but don’t overlap excessively.
If desired, sprinkle chopped walnuts or cranberries over the cinnamon rolls for added texture and flavor.
Bake the casserole in the preheated oven for 25 to 30 minutes, until the cinnamon rolls are golden brown and bubbling around the edges.
Remove from the oven and let it cool for a few minutes, allowing the filling to set slightly and the aroma to fill the room.
Serve warm, spooning generous portions onto plates, letting the caramelized apples and soft cinnamon rolls create a comforting, luscious bite.