Preheat the oven to 350 degrees. Grease a 9X9 baking dish. Set it aside.

To make the cookie layer, combine the sugars and butters in a bowl and mix with a hand mixer. Mix for 2 minutes until it's fluffy.

Add the vanilla and egg and combine.

Grab a different bowl and stir together the baking soda, salt, and flour. Add the butter mixture and beat until combined.

Add the chocolate chips.

Once combined, press the cookie dough into the baking dish.

Add a layer of Oreo cookies on top. (about 16 cookies) Set aside.

To make the brownie layer, mix the butter and sugar in a bowl for 2 minutes. It will be light and fluffy.

Add the vanilla and eggs and beat to combine.

Add flour, cocoa powder, baking powder, and salt in a different bowl. Stir.

A 1/2 of the dry mixture into the butter mixture and beat well. Then add the rest of the dry mixture.

Fold the brownie batter mixture on top of the cookie dough mixture.

Top with crushed Oreos.

Put the pan in the oven and bake for 40-50 minutes. Check at the 35-minute mark by inserting a toothpick to see if it's done.