Preheat the oven to 350°F. Lightly grease a 9" x 13" pan. I prefer to line the pan with parchment paper as well.
In a medium saucepan, over low heat, melt the butter. Stir in the sugar to combine. Return the mixture to the heat until it's hot but not bubbling (about 110°F to 120°F). This took about 1 minute for me. If it separates, give it a stir to recombine.
Transfer the mixture to a large mixing bowl, and stir in the cocoa powder, salt, baking powder, and vanilla extract.
Add the eggs, whisking until smooth.
Using a spatula, stir in the flour just until combined. Then stir in the chocolate chips until evenly mixed throughout. Spoon the batter into the prepared pan and spread into an even layer.
Bake the brownies for 30 minutes, until a toothpick, or sharp knife poked into the center reveals moist crumbs, but not raw batter. The brownies should be set on the edges but still slightly soft in the center. Remove them from the oven, and cool completely on a rack. Cut into squares and enjoy.