Place 1 & 1/2 cups peanuts in the bottom of an ungreased 11″x 7″ pan.*
Melt butter and peanut butter chips in a large saucepan over low heat. Stir until smooth.
Remove from heat. Stir in condensed milk and marshmallows. Continue stirring until smooth and well-blended.
Pour peanut butter mixture over peanuts in pan. Sprinkle remaining 1 & 1/2 cups peanuts over top of peanut butter mixture. If saltier bars are desired, sprinkle lightly with salt.
Cover and refrigerate until chilled. Then, cut into bars. Bars can be served chilled or at room temperature.
Makes about 30 bars.
*These can be made in a 9″x 13″ pan. Use another cup of peanuts, divided between the bottom of the pan and the top of the bars. The same amount of filling will work and give you slightly thinner bars.