Combine corn syrup and sugar in a large saucepan over medium heat. Stir until sugar dissolves and mixture just comes to a boil.
Remove from heat and stir in peanut butter until smooth.
Fold in Rice Krispies cereal until evenly coated.
Press mixture into the prepared pan.
Melt chocolate chips and butterscotch chips together over low heat, stirring until smooth.
Spread melted topping over the cereal base.
Let set completely, then cut into bars.
Notes
Do not boil the sugar mixture longer than needed or the bars can turn hard. Press the cereal mixture gently into the pan; packing too firmly makes dense bars. Let the topping set at room temperature for the best texture. Store covered at room temperature up to 5 days.
Keyword chocolate scotcheroos, no bake bars, scotcheroos