01 - Preheat oven to 350°F. Line an 8x8 inch baking pan with parchment paper.
02 - Whisk melted butter and sugar in a large bowl until smooth. Add eggs, vanilla extract, and mint extract; whisk until well combined.
03 - Sift cocoa powder, flour, and salt into the wet mixture. Stir gently until just combined; avoid overmixing.
04 - Fold semisweet chocolate chips into the batter.
05 - Pour batter into prepared pan and smooth top. Bake for 25-30 minutes until a toothpick inserted in center comes out with moist crumbs.
06 - Let brownies cool completely in pan on wire rack.
07 - Place chopped chocolate and butter in heatproof bowl. Heat cream in small saucepan until simmering, then pour over chocolate. Let stand 1 minute, then stir until smooth and glossy.
08 - Pour ganache over cooled brownies and spread evenly.
09 - Refrigerate for 20-30 minutes until set. Slice into 16 squares and serve.