Preheat your oven to 350°F (175°C) and line your baking pan with parchment paper.
In a medium saucepan over low heat, melt the unsalted butter and let it cool slightly.
In a large mixing bowl, combine the melted butter and granulated sugar, stirring until smooth.
Add the eggs one at a time, mixing well after each addition, then stir in the vanilla extract.
In another bowl, whisk together the Dutch cocoa powder, all-purpose flour, baking powder, espresso powder, and salt.
Gradually add the dry mixture to the wet mixture, stirring gently until just combined.
Fold in the chocolate chips until evenly distributed throughout the batter.
Pour the brownie batter into the prepared baking pan and smooth the top with a spatula. Bake for 25-30 minutes.
Allow the brownies to cool in the pan for at least 15 minutes before lifting them out and slicing.