Preheat the Oven: Preheat your oven to 350°F (175°C). Grease a 9x9 inch baking pan or line it with parchment paper.
Melt Butter and Sugar: In a medium saucepan, melt the butter. Remove from heat, and stir in sugar, eggs, and vanilla.
Add Dry Ingredients: Beat in cocoa, flour, salt, and baking powder. Spread the batter into the prepared pan.
Bake: Bake for 20-25 minutes, or until brownies start to pull away from the sides of the pan. Do not overbake. Let cool in the pan.