In the top of a double boiler, combine peanut butter, butter and marshmallows; cook ... square. Cut into bars and cool. Refrigerate or freeze ... foil or freezer paper.
In heavy saucepan, boil Karo ... Stir in peanut butter and vanilla, mixing well. Add peanuts and Rice Chex, stirring well. Immediately transfer ... and cut into bars. Do not refrigerate.