Preheat oven to 350°F (175°C).
In a mixing bowl, cream together the softened butter, sugar, and brown sugar until light and fluffy.
Add the eggs and vanilla extract to the mixture and beat until well combined.
In a separate bowl, whisk together the flour, baking soda, and salt. Gradually add to the wet mixture and mix until just combined.
Fold in the chocolate chips. Set aside.
For the brownie batter, whisk together the melted butter and sugar until well combined.
Add the eggs and vanilla extract, and mix until smooth.
In another bowl, whisk together the cocoa powder, flour, baking powder, and salt. Gradually add to the wet mixture and mix until just combined.
Spread the cookie dough evenly in the bottom of a greased pie dish.
Pour the brownie batter over the cookie dough, spreading it evenly.
Bake in the preheated oven for 30 minutes or until a toothpick inserted into the center comes out clean.
Let cool before serving. Enjoy!