I've had this recipe since the 1960s when I was a Girl Scout. Easy and delicious!
Heat Karo syrup and sugar just until small bubbles form (watch carefully); remove from heat. Quickly stir in peanut butter; mix well.
Press mixture into greased 9"x13" pan.
Melt chocolate and butterscotch chips in top of double boiler. Spread over Rice Krispies layer. Allow to cool completely until layer has hardened.