Line a 9”x13” baking dish with wax paper. This will make removing the crispy rice treats easy. Set aside.

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

Break the Oreo cookies up with your hands into bite-sized pieces. (You can also put them into a plastic bag and crush them with a rolling pin if you’d rather.)

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

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

Add the splash of vanilla, and stir.

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

Add the cookie chunks, and stir until they’re scattered throughout.

Pour the 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.

Let the treats cool completely, about 1 hour.

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