Melt the butter or coconut oil over low heat in a large pot.
Once the butter has melted add the marshmallows to the pan and heat, stirring frequently until the marshmallows are melted and smooth. Be sure to stir frequently so the marshmallows don't burn.
Turn off the heat and stir in the peanut butter.
Then fold in the cereal.
Transfer the mixture to the prepared baking pan. Gently spread the mixture to fit the pan and press it down lightly so you have an even layer.
Put the chocolate in a microwave safe bowl or dish, and heat it on high for 30 second intervals until melted.
Pour the melted chocolate over the Rice Krispie treats and then transfer the pan to the fridge for 45 minutes to let the chocolate harden, or let them set for 2 hours at room temperature instead.
Cut the treats into pieces and enjoy!
Notes
Nutritional values are an estimate and will vary depending on the exact ingredients used.
The fresher the marshmallows the better these treats will turn out.
Store any leftover treats in an airtight container at room temperature for up to 5 days