Preheat your oven to 350°F (175°C).

In a large mixing bowl, combine the melted butter and granulated sugar. Stir until well combined. Add the eggs one at a time, mixing thoroughly after each addition. Finally, stir in the vanilla extract.

In a separate bowl, whisk together the flour, cocoa powder, salt, and baking powder until mixed well.

Gradually add the dry ingredients to the wet mixture. Stir until just combined; be careful not to overmix. Fold in the chocolate chips if you are using them.

Grease a 9x13 inch baking pan or line it with parchment paper for easy removal.

Pour the brownie batter into the prepared baking pan, smoothing it out evenly.

Bake in the preheated oven for 20 to 25 minutes or until a toothpick inserted into the center comes out with a few moist crumbs.

Let the brownies cool in the pan before cutting them into squares. Enjoy!