Lightly grease a 9x13-inch pan with nonstick cooking spray, and set aside. In a large bowl add the Rice Krispies cereal and set aside.
Unwrap the Butterfingers and place them in a gallon-size ziplock bag. Use the back of a metal spoon or ladle to crush up the candy bars into pieces. Pour the candy bar pieces into a measuring cup. You should have 2 cups of Butterfinger pieces; set aside.
Place the sugar and corn syrup into a large saucepan set over medium heat. Stir the mixture constantly with a rubber scraper until the sugar dissolves and the mixture begins to boil about 3-5 minutes.
Remove the mixture from the heat and stir in the peanut butter until combined.
Pour the peanut butter mixture over the Rice Krispies and stir until the cereal is well coated.
Add in 1 1/2 cups of the Butterfinger pieces to the mixture and stir until evenly distributed.
Pour the mixture into the prepared pan and smooth into an even layer.
MAKE THE CHOCOLATE-BUTTERSCOTCH TOPPING:
Add the chocolate chips and butterscotch chips to a small microwave-proof bowl. Microwave at 50% power in 30-second increments until the chips are melted, stirring after every 30-seconds.
Spread the chocolate mixture over the Scotcheroo bars into an even layer.
Sprinkle the remaining 1/2 cup of Butterfinger pieces over the chocolate.
Let the Scotcheroos sit until they are firm, about 60-90 minutes. Cut into 24 squares and serve.