Step 1

Grease a 9 x 9 inch pan with butter. If desired, line the bottom of the pan with a strip of parchment paper, leaving some overhanging on either side of the pan (see notes 1 - 2). Grease the bottom of the parchment paper with butter (if using). Set the pan aside.

Step 2

Melt 4 tablespoons of the butter in a large pot set over low heat. While the butter is melting, stir it occasionally with a wooden spoon or spatula.

Step 3

When the butter is melted, add the mini marshmallows. As the marshmallows melt, stir them frequently, being sure to scrape the bottom of the pot occasionally to keep the marshmallows from burning.

Step 4

When the marshmallows are about half melted, add in the peanut butter and pinch of salt. Continue to stir frequently, scraping the bottom of the pot, until the marshmallows are completely melted and the mixture is evenly combined.

Step 5

Dump the rice krispies cereal into the pot. Stir gently to evenly combine the cereal with the peanut butter marshmallow mixture. When thoroughly combined, turn the stove off.

Step 6

Quickly scoop the rice krispie treats into the prepared pan. Use a greased spatula to pat the rice krispie treats into an even layer. Do not compress the rice krispie treats, just lightly pat them into place.

Step 7

Add the peanut butter chips and remaining 2 tablespoons butter to a medium microwave-safe bowl. Microwave the bowl on 50% power for 1 minute. Stir the peanut butter chips and microwave at 50% power for an additional 30 seconds, then stir again. If not yet fully melted, microwave for an additional 30 seconds at 50% power, stir again.

Step 8

Spread the melted peanut butter chips over the rice krispie treats in an even layer. Sprinkle the chopped peanuts on top, pressing them down gently to help them stick better.

Step 9

Let the peanut butter rice krispie treats cool fully, about 1 hour at room temperature or 30 minutes in the fridge.

Step 10

When the treats are fully cool and the topping has set, remove them from the pan in one piece using the sides of the parchment paper to lift them out. Cut the rice krispie treats into squares or bars and serve. (If you did not line the pan with parchment, you can cut them into squares while still in the pan.)