Spray a 9 x 13 pan with non-stick spray and set aside. Pour Rice Krispies into a large bowl and set aside.
In a medium-sized saucepan, add sugar and corn syrup. Place the pan on the stovetop over low heat, stirring until just warm, not hot.
Remove the saucepan from heat and stir in peanut butter and vanilla until smooth and well combined.
Pour the peanut butter mixture over the Rice Krispies. Mix well until all the cereal is evenly coated.
Combine chocolate and butterscotch chips in a microwave-safe bowl. Microwave in 30-second intervals, stirring between, until smooth and melted. Spread over the Rice Krispies and let the chocolate harden before cutting.
Notes
Keep the sugar and corn syrup mixture on low heat to prevent overheating;
Stir the Rice Krispies gently to avoid crushing them
Spread the melted chocolate evenly with a spatula
For cleaner cuts, let the scotcheroos cool fully or refrigerate briefly
Balance sweetness by using semi-sweet chocolate chips.