2packages10 ounces each peanut butter chips or substitute one package for chocolate chips
Line a 13x9 inch pan with parchment or wax paper, and spread out half the peanuts.
In a medium sized sauce pan, melt butter over low heat. Add sweetened condensed milk, and stirring constantly, increase heat to medium high.
Add one package peanut butter chips, and mix until melted. Then stir in marshmallows. When they’re mostly melted, remove from heat. Add second package of peanut butter chips or chocolate chips. Stir to incorporate, but don’t wait for them to melt. You can reserve a few chips to sprinkle on top, if you want. Pour mixture over peanuts in pan.
Top with the rest of the peanuts, and gently press them into the bars. Allow to cool completely. I like to do this at room temperature, but if you’re in a hurry, refrigerate for one hour.
Cut into bars of desired size.
Store in airtight container in refrigerator for up to two weeks.