In an extra large bowl, measure out your Rice Krispie Cereal.
In a large microwave safe bowl, melt 2 tbsp of butter completely.
Pour 3/4 of the bag of marshmallows into the bowl and stir to coat with the melted butter.
Return the bowl to the microwave and cook for 30 seconds and then stir. Repeat one more time until the marshmallows are mostly melted.
Add the peanut butter to the bowl and stir to combine.
Pour over the Rice Krispie cereal and stir to coat.
Once everything is combined, add the remaining marshmallows to the mixture and mix until evenly distributed.
Pour into a greased 9×9 pan for extra thick cereal treats or in a 9×13 for normal cereal treats.
Wet your hands slightly and use your damp hands to gently press the mixture into the pan.
Allow the mixture to set in the pan for 30 minutes before cutting and serving.
Enjoy!