Crispy Peanut Butter Bars 1/4 cup butter 1 package (10 ounces) marshmallows 6 cups chocolate flavored crispy rice cereal 1 cup peanut butter chips 1/2 cup chopped peanuts, optional Butter a 13- X 9-inch pan. In a large saucepan over low heat, melt the marshmallows and butter, stirring frequently. Remove from heat and stir in cereal, peanut butter chips, and peanuts, if using; mix until well combined. Press mixture into the pan, cool, and cut into bars. Makes about 32 to 36 bars, depending on size.