Spray an 8 inch baking pan with a non stick cooking spray.

Then place the butter in a small sauce pan. Heat the butter over medium heat. Heat the butter, stirring occasionally with a heat resistant spoon. Watch closely, the butter will turn to a foam, then a caramel color and then the butter with turn a dark brown color. Make sure that the butter does not burn.

Reduce the heat to low, then stir in the marshmallows . Heat on low until the marshmallows are fully melted and the mixture is smooth. Stir constantly while the marshmallows are melting.

Then place the rice krispie cereal in a large bowl. Then pour the marshmallow mixture over the rice krispies. Stir together to make sure that the cereal is covered.

Then pour the mixture into an 8 inch baking pan. Spray a piece of parchment paper with a non-stick cooking spray and use that parchment paper to press the mixture