Preheat oven to 350 degrees. Line an eight inch baking pan with foil making sure to let the foil over hang on sides to left out the brownies. Grease the foil with shortening Or grease the pan with shortening.

Place the butter in a medium size saucepan. Over low heat, cook the butter until just melted. Remove from the heat. Add the sugar and vanilla, whisk until well combined. When the mixture has cooled, add the eggs and whisk until well incorporated.

Place the flour, cocoa, baking powder and salt in a medium size bowl, whisk to combine. Gradually whisk the flour mixture into the butter mixture until just incorporated. Fold in chocolate chips or nuts if using.

Pour the batter into your prepared pan, spread evenly to the edges of the pan.. Bake at 350 degrees for 20 - 25 minutes or until edges of brownies pull away from the sides of the pan. Cool completely, cut and serve.