Stir. If necessary, microwave at additional 10- to 15-second intervals, stirring just until morsels are melted.
Spread over cereal mixture.
Chill for 15- 20 minutes or until topping is firm. Cut into bars.
Notes
Peanut butter: I don't recommend using natural peanut butter in this recipe. Regular creamy peanut butter works well.
Corn syrup: Corn syrup helps to make the bars chewy and keep the sugar from crystalizing.
Cereal: Scotcheroos are traditionally made with Rice Krispie cereal, but there's no reason why you couldn't use a different type of cereal if you prefer.