Start by preheating your oven to 350°F (175°C). This will ensure that your brownies bake evenly.
Line an 8x8-inch baking pan with parchment paper, leaving some overhang on the sides for easy removal.
In a medium saucepan over low heat, combine the chopped dark chocolate and 1 cup of unsalted butter. Stir until melted and smooth. Remove from heat and let it cool slightly.
In a large mixing bowl, whisk together the melted chocolate mixture, 2 large eggs, 1 cup of granulated sugar, 1 tablespoon of vanilla extract, 1 tablespoon of brewed coffee, and 1 teaspoon of instant espresso granules until well combined.
In another bowl, sift together 1 cup of all-purpose flour and 1/2 teaspoon of salt. Gradually fold the dry ingredients into the wet mixture using a rubber spatula until just combined. Be careful not to overmix!
Gently fold in the unwrapped peanut butter cups, making sure they’re evenly distributed throughout the brownie batter.
Pour the brownie batter into the prepared baking pan, spreading it evenly. Bake in the preheated oven for 25-30 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs.
Once baked, remove the brownies from the oven and let them cool in the pan for about 10 minutes. Using the parchment paper overhang, lift the brownies out of the pan and transfer them to a wire rack to cool completely before slicing into squares.
