Preheat the oven to 350 degrees (175 degrees C), line your pan with parchment paper.In a bowl, first whisk the butter and brown sugar, then addthe 2 eggs, vanilla and milk, mix together well. Add the melted chocolate and whisk it well. Then add the flour, cocoa powder, salt and baking powder andmix it well until they are well blended. add the batter into the prepared baking pan and bake it for about 25-30 minutes.