Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking pan.
In a large bowl, combine melted butter and sugar.
Add eggs one at a time, mixing well after each addition.
Stir in vanilla extract until well blended.
In another bowl, whisk together flour, cocoa powder, salt, and baking powder.
Gradually add the dry ingredients to the wet mixture, stirring until combined.
Pour the batter into the prepared baking pan, spreading it evenly.
Bake for 25-30 minutes, or until a toothpick inserted in the center comes out clean.
Allow the brownies to cool in the pan for 10 minutes before transferring them to a wire rack.
Cut into squares and serve. Enjoy!