Prepare the Shortbread Crust
Preheat your oven to 350°F (175°C) and line a 9×13-inch baking pan with parchment paper, leaving some overhang on the sides to use as “handles.” In a medium bowl, combine the dry cake mix and melted butter. Mix until a crumbly dough forms, then press it evenly into the bottom of the prepared pan.

Make the Cheesecake Layer
In a large bowl, beat the softened cream cheese until smooth. Gradually mix in the sweetened condensed milk until well combined. Beat in the eggs one at a time, followed by the vanilla extract. Pour this smooth batter evenly over the crust.

Prepare the Apple Topping
In a separate bowl, toss the finely diced apples with the brown sugar, caramel sauce, flour, and cinnamon until the apples are evenly coated. The flour helps to thicken the juices from the apples as they bake.

Assemble and Bake the Bars
Evenly scatter the apple mixture over the cheesecake layer. Place the pan in the preheated oven and bake for 40 to 50 minutes, or until the cheesecake is set and the edges are golden. Let the bars cool completely at room temperature, then chill them in the refrigerator for at least 3 to 4 hours to firm up before slicing.

Drizzle with Caramel
Just before serving, lift the bars out of the pan using the parchment paper handles. Drizzle generously with additional caramel sauce and slice into squares.