Line a 9×13 inch baking dish with parchment paper and lightly grease the parchment, or grease/butter your baking dish. Set aside.
Using a very large pot, melt the butter over medium heat. Once melted, add the marshmallows. Stir the mixture, using a rubber spatula, until the marshmallows are almost completely melted. Add in the peanut butter** and mix until combined.
Turn off the heat and add the salt, stir and pour in the cereal and mix quickly to combine everything. Make sure all of the cereal is coated with the marshmallow mixture.
Transfer the mixture to your prepared baking dish. Using a rubber spatula (greasing it if needed), spread the mixture into the baking dish, using your rubber spatula to press down into the dish. Let sit for at least 1 hour at room temperature. Cover with saran wrap if leaving out for more than a few hours.
When ready, carefully lift the rice krispie treats (in one piece) out of the pan and cut into squares. Dip one corner of each into melted chocolate and let cool on parchment paper. To store: After cutting into squares, I wrap any leftover individual squares with saran wrap. (I wrap them individually. They are best 3-4 days after making.) Enjoy!