Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking pan and line it with parchment paper, leaving some overhang for easy removal.
In a large saucepan over medium heat, melt the unsalted butter. Once melted, remove from heat and stir in the granulated sugar and brown sugar until well combined.
Allow the mixture to cool slightly before whisking in the eggs, one at a time, followed by the vanilla extract.
In a separate bowl, sift together the flour, cocoa powder, baking powder, and salt. Gradually fold the dry ingredients into the wet mixture until just combined.
Stir in the cooled brewed coffee and peppermint extract, followed by the chocolate chips. Be careful not to overmix.
Pour the brownie batter into the prepared baking pan and spread it evenly.
Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
Let the brownies cool in the pan for about 10 minutes, then lift them out using the parchment paper and allow them to cool completely on a wire rack.
Once cooled, cut into squares and serve with a dollop of whipped cream on top, if desired, and garnish with fresh mint leaves.
Notes
Serve with whipped cream and fresh mint for an extra touch.