Lightly grease a 9×13-inch pan with butter or cooking spray.

This will make it easier to remove the bars once they’re set.

Measure out 6 cups of Rice Krispies cereal and pour into a large bowl.

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

Add the marshmallows and stir continuously until they’re completely melted and smooth.

Remove the pot from heat and immediately fold in the Rice Krispies cereal, making sure each piece is coated in the marshmallow mixture.

Pour the mixture into your prepared pan, using a spatula or lightly buttered hands to press it down evenly.

Avoid pressing too hard; this keeps the bars nice and soft.

Let the bars cool completely at room temperature before cutting them into squares. Enjoy!