Preheat oven to 350°F and grease 8x8 inch pan.
Melt butter in a medium saucepan on stove top. Remove from heat.
Pour melted butter in a large mixing bowl. Stir in sugar, eggs and vanilla.
Sift dry ingredients together cocoa, salt, baking powder, and flour into the bowl with butter mixture. Mix batter well.
* Optional, Add chocolate, white chocolate, peanut butter chips, walnuts or fudge to or on top of batter.
Pour batter into pan, spread evenly. Cook for 30 minutes or stick a toothpick into center to be sure it comes out clean.
Allow brownies to cool. Cut into 9 squares.
* Optional, Add chocolate, white chocolate, peanut butter chips, walnuts or fudge to or on on top of batter.