Preheat your oven to 350°F (175°C) and prepare an 8x8-inch baking dish by lining it with parchment paper, allowing the edges to hang over for easy removal later.
In a medium-sized mixing bowl, combine the graham cracker crumbs, melted butter, and brown sugar. Stir until the mixture is well incorporated and resembles wet sand. Press this mixture firmly and evenly into the bottom of the lined baking dish to create a sturdy crust. Bake in the preheated oven for 8 minutes, then remove and set aside to cool while you prepare the filling.
In a large mixing bowl, use an electric mixer to beat the softened cream cheese until smooth and creamy, about 2-3 minutes. Gradually add the granulated sugar, mixing continuously until fully combined and fluffy.
Add the eggs one at a time, mixing on low speed after each addition just until incorporated. Then, mix in the vanilla extract and ground cinnamon, ensuring everything is evenly combined.
Gently fold in the peeled and diced apples and the caramel sauce, being careful not to overmix. You want to distribute the apples evenly throughout the cheesecake mixture.
Pour the cheesecake filling over the cooled graham cracker crust, smoothing the top with a spatula for an even layer. If using, sprinkle the optional chopped nuts evenly across the top.
Bake in the oven for 30-35 minutes. The edges should appear set, while the center should have a slight jiggle; it will firm up as it cools.
Once baked, remove the cheesecake bars from the oven and allow them to cool to room temperature in the baking dish. After cooling, transfer to the refrigerator and chill for at least 2 hours, or until fully chilled.
When ready to serve, use the parchment overhang to lift the cheesecake bars out of the pan. Cut into squares or bars for serving. Drizzle with additional caramel sauce for a delightful finishing touch.
Notes
Arrange the cheesecake bars on a decorative platter. Drizzle caramel sauce over each bar and sprinkle with crushed nuts for added texture.