Preheat your oven to 350°F (175°C). Line the baking sheet with parchment paper, allowing some overhang for easy removal.
In a large mixing bowl, melt the butter. You can do this in the microwave or on the stovetop until fully melted.
Once melted, whisk in the granulated sugar until combined.
Add in the eggs one at a time, whisking well after each addition. Then, stir in the vanilla extract.
In a separate bowl, mix together the flour, cocoa powder, baking powder, and salt.
Gradually add the dry ingredients into the wet mixture, stirring until just combined. Be careful not to overmix.
If desired, fold in the chocolate chips.
Pour and spread the batter evenly into the prepared baking sheet.
Bake in the preheated oven for 25 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs or clean.
Once done, remove the brownies from the oven and let cool completely in the baking sheet on a wire rack.
Once cooled, use the parchment overhang to lift the brownies out of the pan, and cut into equal squares.