Preheat oven to 350 degrees and line an 8×8 inch baking dish with foil that’s sprayed with cooking spray.
Place butter and sugars into a large bowl, cream until well combined. Add peanut butter mixing to combine. Add egg and vanilla mixing well. Add flour, baking soda and salt, mixing until dough forms. Add chips and mini Oreo cookies stirring until just combined. Transfer dough to prepared baking dish, press dough evenly into pan.
Bake for 30-35 minutes or until golden brown and cooked through. Remove and let cool for 45 minutes before cutting into squares. Serve with milk and enjoy!