premise: How do you press rice krispy treat mixture into the pan?
hypothesis: Grease the pan with spray. Grease a small, slotted serving spoon. Pour the cooled cereal-marshmallow mix into the greased pan, using the greased spoon to get all of the mixture out of the pan. Use the back of the greased spoon to slowly and carefully press the cereal mixture into the pan. Slide the spoon over the cold cereal, pressing gently, more toward the middle than the sides. Dip the spoon in more oil to re-grease it as needed.