My grandmother was famous for a wide variety of sweet treats, from cookies to bars to doughnuts. Scotcheroos were always one of my favorites. I consider them an upgrade of the standard Rice Krispie bar (her extra-buttery version of those is also a family classic), incorporating peanut butter, chocolate, and butterscotch. They're a quintessential Midwestern "bar." Enjoy with a cup of black coffee after finishing your hotdish.
While I enjoyed them for years, I never knew anything about their origin or attempted to make them myself. I found this recipe in the same church cookbook as my meatloaf recipe from January. I did some cursory internet research and was surprised to find an amazing level of consistency across recipes. There is a little variance in the amount of chocolate and butterscotch, but for the most part, the recipe is unchanged. With a little more digging, I discovered the recipe appeared on the side of a Rice Krispies box in 1965, and the recipe has been passed around ever since.
I haven't reinvented the recipe, but having now made them myself, I do have comments. The corn syrup/sugar mixture is extremely sticky, as it functions as the glue to turn the cereal into a cohesive bar. It's important to move quickly to get the cereal coated and into the dish before it solidifies. It was a little tricky to get into an even layer an into the corners. Avoid the temptation to press down too much as these are already quite dense. The recipe I have doesn't mention this, but I would recommend buttering the dish to help get the bars out.