Lightly grease a 9X13-inch pan with butter or cooking spray or line with foil/parchment and grease the foil/parchment. Set aside.
In a large saucepan or pot, add the butter, corn syrup, granulated sugar and brown sugar. Cook on low heat until the butter is melted. Bring to a simmer and immediately remove from the heat.
Stir in the peanut butter and vanilla until well-combined.
Add the cereal and stir gently (so the cereal doesn't get crushed) until evenly coated with the peanut butter mixture.
Press the mixture lightly into the prepared pan. Don't compress too much or the scotcheroos will be too firm.
Add the chocolate chips and butterscotch chips to a microwave-safe bowl and cook for 1-minute increments at 50% power until melted. Stir until well-combined.
Spread the melted chocolate mixture evenly across the bars. Let the chocolate cool and set before cutting into bars and serving.
Notes
Peanut Butter: I always make these with creamy peanut butter (like Jif or Skippy). Feel free to experiment with chunky peanut butter or with a natural-type peanut butter or nut butter alternative.Pan Size: if you want the scotcheroo rice krispie base a bit thinner, you can use a larger pan. You can also play around with the rice krispie amount - adding more or less - for a gooier/less gooey version, depending on how you like them.