If you don't want to use Cocoa Powder, you can change it into 150 grams of melted chocolate!
Mix the Sugar, the melted butter and the Cocoa Powder.
Add the Eggs an the Vanilla extract
Add the flour
And the baking powder
Mix well until it gets like this
Put the batter on a buttered and floured baking tray
Cook in low oven for about 20-25 minutes
Ready! Let it cool down, then, cut into squared pieces