Heat oven to 350 F.
Grease 9” square baking pan.
In large mixing bowl mix butter, sugar, vanilla, and eggs, until no lumps.
In separate bowl mix flour, cocoa, baking powder, and salt with whisk.
Then slowly add into wet mix in large bowl.
Stir in nuts.
Spread batter evenly into the prepared pan.
Bake 20-25 minutes or until brownies begin to pull away from sides.
(If recipe is doubled, bake for 35 minutes, double frosting recipe as well.)