Butterscotch Marshmallow Squares

One of my aunts just made these yesterday and they bring me right back to a school Hallowe'en party in 1988. And the subsequent years that a friend's Mum made them...

BUTTERSCOTCH MARSHMALLOW SQUARES

1 (12 oz.) pkg. butterscotch chips
1/4 c. butter
1 c. smooth peanut butter
1 pkg. miniature rainbow marshmallows

Combine butter and peanut butter and butterscotch chips in a double boiler on low - medium heat until melted. Take off heat and cool mixture before adding marshmallows. Pour mixture into ungreased cake pan. Spread evenly. Refrigerate until cold and cut into squares. Keep in refrigerator.