Add butter to a small saucepan and melt over medium-low heat.
In a mixing bowl add the first cup of chocolate chips and pour the melted butter on top. Wait a minute before mixing them together until the chocolate chips are melted and smooth.
Add in the granulated and brown sugars and mix again until combined.
Add the eggs and vanilla. Mix until incorporated.
Add the baking powder, flour, salt and cocoa powder. Fold in the dry ingredients until a thick dough has formed.
Add the rest of the chocolate chips and fold into the dough. The dough should be similar to the consistency of a regular brownie batter.
Cover the bowl in plastic wrap and refrigerate for 30 minutes.
Preheat oven to 350 degrees Fahrenheit and prepare a baking sheet with parchment paper.
Remove the chilled dough from the fridge and use a 2 inch scooper to scoop out balls of cookie dough. Place each ball on the baking sheet about 2 inches apart from each other.
Bake in the oven for 11-13 minutes or until the tops of the brownie cookies are crinkly and the edges are firm.
Let cool for at least 5 minutes and serve while warm!