Preheat your oven to 350°F (175°C). Grease a 9x13 inch baking pan or line it with parchment paper for easy removal.
In a large mixing bowl, whisk together the melted butter, granulated sugar, and brown sugar until well combined.
Add in the eggs, one at a time, mixing well after each addition. Stir in the vanilla extract.
Sift together the flour, cocoa powder, and salt in a separate bowl. Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the chopped pecans, reserving a handful for topping.
Pour half of the brownie batter into the prepared baking pan and spread it evenly.
Drizzle half of the caramel sauce over the brownie layer, then sprinkle the reserved pecans on top.
Pour the remaining brownie batter over the caramel and pecans, spreading it evenly to cover.
Finally, drizzle the remaining caramel sauce over the top and use a knife to swirl it slightly into the brownie batter.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
Once baked, remove the brownies from the oven and allow them to cool in the pan for about 15 minutes before lifting them out using the parchment paper (if used) and transferring them to a wire rack to cool completely.
After cooled, cut into squares and sprinkle a few sea salt flakes on top for added flavor.
Notes
Allow brownies to cool completely before cutting for best results.