• Step 1: Melt the butter in a large saucepan over medium heat. Once melted, add the marshmallows and stir constantly until they are completely melted and the mixture is smooth, about 5 minutes.
• Step 2: Remove the pan from the heat and immediately stir in the Rice Krispies cereal, mixing until the cereal is evenly coated with the marshmallow mixture.
• Step 3: Lightly grease a 9×13-inch baking pan. Using a spatula or your hands, press the mixture evenly into the prepared pan. Allow to cool completely before cutting into squares.