I modified since it was just for me and Jon, but I didn't modify correctly (blame it on a sore neck and not me being a complete doofus). I used the full amount of peanut butter and butter, then cut the cereal and marshmallows.
It tastes great, but it's extremely gooey and not easy to handle. I put it in the fridge for a little while to see if it would harden up. I suppose if it doesn't, it's good to eat with a spoon. Still, next time I'll make sure to halve everything and not just the things that would have, you know, made this a finger dessert rather than an ice cream topping.