Start as a chef and preheat your oven to 350 F before moving to the other steps.
Bring a 9*13 inches non-stick baking dish and spray it with cooking spray.
Melt the butter in a microwave-safe bowl then mix the cocoa powder with it.
In a separate large bowl, whisk the eggs, vanilla, and sugar then add in the butter and cocoa mixture you already made and mix all together until well-combined. Add the dry ingredients to this mixture which are the flour, salt and baking powder and stir until all the ingredients are well-blended but avoid over-mixing.
Pour the batter in the already prepared baking dish and bake it on the middle rack of your oven not the top for about 25 minutes.
When you remove the baking dish from the oven let your brownie cool then cut it into small squares with a dry knife then you can serve for chocolate brownies lovers.