Grease 9 x 13 cake pan. Sprinkle 1/2 of a 16 ounce jar dry roasted peanuts in the pan. Melt and mix 3 tablespoons butter and 12 ounce package of peanut butter chips over low heat. Remove from heat. When creamy, add 1 can sweetened condensed milk. Fold in 1/2 package of miniature marshmallows. Spread on peanuts and press down. Sprinkle other half of jar of peanuts on top and press down again. Keep in refrigerator.