Begin by preheating your oven to 350°F (175°C). Prepare a 9x13-inch baking pan by either greasing it well with butter or lining it with parchment paper for easy removal of the brownies later.
In a medium saucepan, place the unsalted butter and melt it over low heat. Stir occasionally to ensure it melts evenly. Once the butter has completely melted, remove it from the heat and mix in the granulated sugar and packed brown sugar until they are thoroughly combined.
Allow the butter and sugar mixture to cool for a few minutes, then add the eggs one at a time, whisking well after each addition. Finish by incorporating the vanilla extract until your mixture is silky and smooth.
In a separate mixing bowl, sift together the all-purpose flour, cocoa powder, baking powder, and salt. Gradually fold this dry mixture into the wet ingredients, mixing gently until just combined. Be careful not to overmix to maintain a fudgy texture.
Once the flour mixture is incorporated, stir in the semi-sweet chocolate chips, ensuring they are evenly distributed throughout the batter for a delicious chocolate bite in every piece.
Pour half of the brownie batter into the prepared baking pan, spreading it evenly across the bottom. Drizzle half of the salted caramel sauce over this layer, giving it a luscious, sweet contrast.
Carefully pour the remaining brownie batter over the caramel layer, ensuring an even distribution. Using a knife or toothpick, gently swirl the caramel into the top layer of brownie batter to create a marbled effect.
Finish by drizzling the remaining salted caramel sauce over the top and swirling it again for an appealing pattern.
Place the pan in your preheated oven and bake for 25 to 30 minutes. To check for doneness, insert a toothpick into the center; it should come out with a few moist crumbs rather than wet batter.
Once your brownies are baked to perfection, remove them from the oven and let them cool in the pan for at least 10 minutes. Just before serving, sprinkle a pinch of sea salt on top for that delightful sweet and salty flavor combination.
Notes
For an extra touch, consider adding a drizzle of additional caramel and a light dusting of sea salt right before serving.