Preheat oven to 350°F
In a mixing bowl, combine butter, eggs, brown sugar, granulated sugar, salt, baking powder, baking soda, vanilla extract, and all-purpose flour. When all ingredients are added into the mixing bowl, stir until the cookie batter begins to pull together. Add chocolate chips, then stir just to combine. Set aside.
Next, in a fresh mixing bowl combine butter, vegetable oil, eggs, granulated sugar, cocoa powder, vanilla extract, salt, baking powder, and all-purpose flour. Once all ingredients are added into the mixing bowl, stir to combine. When the batter is mixed, add chocolate chips. Stir only until combined.
Now that both batters are made, take your cake pan and spray it with cooking spray. Next, form raw cookie dough into balls and place it randomly on the bottom of your cake pan. Pour the brownie batter over the top of the first layer of chocolate chip cookie dough. Next, add more chocolate chip cookie dough on top of the brownie batter. Cover with aluminum foil and bake for 35 minutes at 350°F. after the time is up, check on your bars to see if they are done. They may need more time to bake. Set your timer for 5 or 10 minutes and then check on your bars again. Repeat until the bars are baked to your liking. Remove from the oven and allow to cool before cutting into squares. Once cooled, cut into squares, serve, and enjoy!