Preheat your oven to 350°F (175°C).
Line a 9x13-inch baking pan with parchment paper, leaving some overhang on the sides.
In a medium saucepan over low heat, melt the unsalted butter. Stir occasionally until completely melted, then remove from heat and allow to cool slightly.
Once the butter is cool, add the granulated sugar and Dutch-process cocoa to the pan. Whisk until well combined and smooth.
Add the eggs, one at a time, whisking well after each addition. Stir in the vanilla extract until combined.
In a separate bowl, whisk together the all-purpose flour, baking powder, and salt. Gradually add this dry mixture to the wet ingredients, stirring gently until just combined.
Gently fold in the semi-sweet chocolate chips until evenly distributed throughout the batter.
Pour the brownie batter into the prepared baking pan and spread it evenly. Bake in the preheated oven for 25-30 minutes.
Once baked, remove the brownies from the oven and let them cool in the pan for about 10 minutes. Then, lift them out of the pan using the parchment overhang and onto a wire rack to cool completely.