Preheat the oven to 350.
Spray a 9×13-inch baking pan generously with Pam or for easy cleanup line pan with foil and grease the foil really well with butter or non stick cooking spray. In a large, microwave-safe bowl, combine the chopped chocolate and butter. Microwave in intervals of 1 minute at 50% power until the chocolate is melted and the mixture is smooth, stirring in between intervals.
Whisk in the sugar, eggs and vanilla until incorporated. Stir in the flour and salt just until combined.
Spread about half of the brownie batter in the bottom of the prepared pan in an even layer. Bake for 18 minutes. While they are baking, make the caramel filling.
Meanwhile, while the brownies are cooking, add the chopped pecans (if using) to a medium skillet over medium heat. Toast, stirring occasionally, until fragrant and light golden brown. Remove from the heat and set aside.
To make the caramel filling, combine the caramels and cream in a medium microwave-safe bowl. Microwave for 30 seconds at 50% power. Stir. Repeat the process, keeping a close eye on the mixture as it can burn very easily (make sure you use low heat in the microwave). Continue the microwave process until the caramels and cream are melted and combined. Stir in half of the pecans to the caramel mixture. Immediately spread the caramel mixture over the bottom brownie layer.
Scoop the remaining brownie batter in spoonfuls over the caramel layer and spread it evenly across the caramel layer (spooning the batter in piles over the caramel will help to get an even layer of batter over the caramel).
Sprinkle the chocolate chips and the remaining pecans on top of the final brownie layer. Bake for an additional 20 minutes. Transfer to a wire rack and let cool completely before slicing and serving. I found the brownies sliced easier once they had been cooled and refrigerated for an hour or two.
Slice the brownies and lift from the pan with a spatula, or lift using the edges of the foil. Remove the foil and cut the brownies into individual squares. Store in an airtight container.