Preheat your oven to 350°F (175°C). Grease your 9x13 inch pan or line it with parchment paper for easy removal.
In a microwave-safe bowl or over low heat on the stove, melt the butter until fully liquid. Stir in the granulated sugar until well combined. This mixture will be slightly grainy but that’s okay—it helps create the glossy brownie top.
Beat in the eggs one at a time, mixing well after each addition. Then stir in the vanilla extract. Your batter will start to get thicker and shiny.
In a separate bowl, sift together the all-purpose flour, cocoa powder, baking powder, and salt. Sifting ensures no lumps and a smooth batter.
Gradually fold the dry ingredients into the wet mixture using a spatula. Mix just until combined—overmixing can make the brownies tough.
Pour half the brownie batter into the prepared pan and spread evenly. Drizzle half of the caramel sauce over it. Carefully spread the remaining brownie batter on top. Finish by swirling the remaining caramel across the surface with a knife or skewer to create beautiful caramel ribbons.
Bake for 30-35 minutes, or until the edges are set but the center still looks slightly underbaked—this keeps them fudgy. Remove from oven and immediately sprinkle the teaspoon of sea salt evenly over the top.
Allow the brownies to cool completely in the pan on a cooling rack. This step is crucial for the fudgy texture. Once cool, cut into squares and enjoy!