01 - Preheat oven to 350°F. Line an 8x8 inch baking pan with parchment paper, ensuring the paper overhangs the edges for easy removal.
02 - In a large mixing bowl, whisk together melted butter and granulated sugar until smooth and fully incorporated. Add eggs, vanilla extract, and mint extract; continue whisking until the mixture appears glossy and well-blended.
03 - Sift cocoa powder, flour, and salt directly into the wet mixture. Using a spatula or wooden spoon, fold gently until just combined—avoid overmixing to prevent tough brownies. The batter should be thick and fudgy.
04 - Fold semisweet chocolate chips into the batter, distributing them evenly throughout.
05 - Transfer batter to the prepared pan, spreading evenly with an offset spatula. Bake for 25–30 minutes until a toothpick inserted in the center emerges with moist crumbs (not wet batter).
06 - Allow brownies to cool in the pan on a wire rack until completely room temperature—approximately 45 minutes to 1 hour.
07 - Place chopped dark chocolate and butter in a heatproof bowl. Heat heavy cream in a small saucepan until just simmering (do not boil). Pour hot cream over chocolate and butter; let stand for 1 minute. Stir vigorously with a whisk until completely smooth and glossy.
08 - Pour the warm ganache over the cooled brownies, using an offset spatula to spread it into an even layer.
09 - Refrigerate for 20–30 minutes until the ganache is firm to the touch. Remove from the refrigerator 10 minutes before slicing.
10 - Using a sharp knife, cut into 16 equal squares. Wipe the knife clean between cuts for clean edges. Serve at room temperature.