Line a 9”x13” baking dish with wax paper. This will make removing the crispy rice treats easy. Set aside. Alternately, you can spray it with nonstick baking spray.

Pour the crispy rice cereal into the large bowl, and set aside.

Place the Oreos in a plastic bag and crush they are in until bite-sized pieces. Set aside.

In a large pot, melt the butter over low heat.

Once the butter has melted, stir in the marshmallows. Continually stir until completely melted.

Pour the cereal and cookies into the marshmallow mixture, and stir quickly until the cereal is coated.

Pour the cereal bar mixture to the prepared baking pan and gently spread the mixture into an even layer with a rubber spatula. (If the mixture begins sticking, spritz the spatula with the nonstick cooking spray.) Do not press down hard on the mixture, as your treats will be more compact.

Add an even layer of sprinkles on top of the treats.

Let the treats cool completely, about 30 minutes to an hour.

Cut with a sharp knife, and enjoy within 2-3 days.