To make the brownie mix, prepare a 8 x 8 square baking pan lined with parchment paper. Allowing the paper to hang over the edges so you can lift it out.
Preheat oven to 350ºF.
Melt down the butter in a bowl and then add in the sugar and mix together. Let cool for 5 minutes.
Once cooled, add in the egg, vanilla and whisk until smooth.
In another bowl mix the cocoa powder, salt, baking powder and flour and then stir that into the wet mix. Stir in the chocolate chips and then set aside.
Make the cookie batter by melting down the butter in a bowl and then add sugar and mix and let cool for 5 minutes, same as how you did the brownies.
Add in the eggs, vanilla and whisk until smooth.
In a separate bowl add the flour, baking powder and salt and mix until smooth then fold in the chocolate chips.
Using a rubber spatula scoop the brownie batter into the pan first spreading evenly. Then take tablespoons of cookie batter and place down on the top of the brownies in rows.
Place in the oven and bake for 35-38 minute or until middle comes out clean on toothpick.