Line a 9x13 baking dish with parchment paper or aluminum foil. Use binder clips to keep the sides of the parchment paper in place, if needed. Spray the parchment paper/foil with nonstick cooking spray and set aside.

In a large saucepan, add the butter. Place over medium heat and let the butter melt.

Once the butter is completely melted, add in the marshmallows and stir until they’re melted and there are no lumps.

Stir in the vanilla extract until combined.

Add the chopped Oreos, chopped white chocolate and rice krispies cereal. Stir until everything is evenly covered with the marshmallow mixture.

Scoop the rice krispies mixture into the prepared 9x13 baking pan.

Lightly spray a piece of wax paper or parchment paper with nonstick cooking spray. Place it on top of the rice Krispies mixture and gently press down. If you press hard, you’ll have a firmer rice Krispies treat.

Let the treats cool before cutting into them.