Begin by greasing your 9x13 inch baking dish and setting it aside. This will help prevent your delicious creation from sticking.
In a large saucepan over medium heat, combine the 10 oz of miniature marshmallows and 1 cup of butter. Stir continuously until the mixture is completely melted and smooth. Make sure not to let it boil.
Once the marshmallow and butter mixture is melted, remove it from the heat. Immediately add in your 6 cups of cocoa Krispies cereal. Stir well to ensure every piece is coated with the marshmallow mixture.
In a separate bowl, mix together the 7 oz jar of marshmallow crème and ½ cup of creamy peanut butter until smooth. Fold this mixture into the rice cereal mixture until well combined.
Gently fold in the 2 cups of roughly chopped Reese's peanut butter cups, being careful not to break them apart too much. You want those delicious chocolatey chunks to stay intact!
Transfer the mixture to your greased baking dish. Using a spatula, evenly spread the mixture across the dish, pressing down firmly to create a compact layer. Allow it to cool for about 15 minutes until it’s set but not completely hardened.
Once slightly cooled, place a large piece of plastic wrap on your countertop. Flip the Rice Krispie treat mixture onto the plastic wrap, and carefully roll it into a log shape, using the wrap to help you. Tightly wrap the pinwheel and refrigerate for at least 30 minutes to firm up.
After chilling, unwrap the log and place it onto a cutting board. Using a sharp knife, slice into 1-inch thick pinwheels. Serve immediately or store for later!
