Begin by preheating your oven to 350°F (175°C). Prepare a 9x13 inch baking pan by greasing it and lining the bottom and sides with parchment paper, allowing some excess to hang over the edges for easy removal later.
In a large mixing bowl, blend together the melted butter, granulated sugar, and packed brown sugar. Use a whisk to mix until the mixture is smooth and well combined.
Introduce the eggs to the mixture one by one, whisking thoroughly after each addition to ensure they are fully incorporated. Stir in the pure vanilla extract until smooth.
In a separate bowl, sift together the all-purpose flour, unsweetened cocoa powder, baking powder, and fine sea salt. Gradually fold this dry mixture into the wet ingredients using a spatula, taking care to avoid overmixing to maintain a fudgy texture.
Carefully stir in the semi-sweet chocolate chips, ensuring they are evenly distributed throughout the batter. Transfer the brownie batter into the prepared baking pan and use a spatula to smooth the top for an even surface.
Bake in the preheated oven for 25-30 minutes. To check for doneness, insert a toothpick into the center of the brownies; it should come out with a few moist crumbs attached. Allow the brownies to cool completely in the pan on a wire rack.
While the brownies cool, prepare the chocolate ganache. In a small saucepan, heat the heavy cream over medium heat until it begins to simmer gently.
Remove the saucepan from the heat and immediately add the finely chopped chocolate and the tablespoon of butter. Allow the mixture to sit for about one minute, then whisk vigorously until it becomes a smooth and glossy ganache.
Once the brownies are completely cooled, carefully lift them out of the pan by pulling on the overhanging parchment paper. Cut into squares of your desired size.
Drizzle the luscious chocolate ganache generously over each brownie square. For an added touch of elegance and flavor contrast, sprinkle a light dusting of sea salt over the top of the ganache.
Notes
For an added touch of elegance, serve with fresh mint leaves or raspberries.