This is a test of commonsense. Complete the next sentence:

How to make rice krispie monster treats
Prepare a 9 x 13-inch baking pan.
You can choose to grease the pan by spraying non-stick cooking spray all over it, or you can cover the pan with parchment paper.
Melt the butter in a medium-sized pan over lower heat.
Stir gently with a rubber spatula until fully melted. Fold in the marshmallows and mix once more until the marshmallows melt.