Preheat the oven to 350°F (175°C). Grease or line a 9x13-inch baking pan with parchment paper.
Prepare the brownie batter according to the package directions and spread it evenly into the prepared pan.
In a large bowl, beat the softened cream cheese and sugar until smooth. Add the eggs one at a time, then mix in the vanilla extract.
Carefully spread the cheesecake mixture over the brownie batter.
Bake for 45–50 minutes, or until the cheesecake layer is set and the center has only a slight jiggle.
Remove from the oven and allow the bars to cool completely.
Drizzle the caramel sauce evenly over the cheesecake layer.
Sprinkle the toasted pecans over the caramel.
Drizzle the melted chocolate over the top in a decorative pattern.
Refrigerate for at least 2 hours before slicing into bars.
Serve chilled or at room temperature.