Have you ever eaten a fluffernutter? It's a sandwich made with peanut butter and marshmallow creme, and sugar-craving kids love it. I have made peanut butter fudge with marshmallow creme, but the idea of putting those things between two slices of white bread makes me ill. Be that as it may, the term fluffernutter goes back to the 1960s, but the sandwich was invented in 1918. That's long enough to declare the fluffernutter an American tradition, but you might be surprised to learn that the woman who invented it, Emma Curtis, did so to promote Snowflake Marshmallow Creme. At the time, that was a new product of the Curtis Marshmallow Company, which she founded with her brother. And so it goes. When you develop a new food product, you have to tell people how to use it.
A whole slew of your family's traditional recipes started out as promotional gimmicks. You shouldn't be surprised to find that Grandma's beloved pineapple upside-down cake with nuts came from a recipe on the back of a can of Dole pineapple rings. Read about these and more traditional American recipes that started out as product marketing at Atlas Obscura.
(Image credit: Kimberly Vardeman)
But you're right about peanut butter and mayo... yecch!