Preheat oven to 350 degrees F. and line 9 x 13 inch baking dish with parchment paper.
Press peanut butter cookie dough layer into baking dish. I used THIS recipe. Use whatever peanut butter cookie dough recipe you’d like. Place cake mix, butter and egg into a large bowl. Mix until dough consistency forms. Press over peanut butter cookie layer. Top with marshmallows and chocolate chips. Bake for 35-40 minutes until baked through. Let cool completely then cut into bars and serve room temperature.