Cheeseburgers

Cheeseburgers weren't possible before the 20th century:

Tomatoes are in season in the late summer. Lettuce is in season in in the fall. Mammals are slaughtered in early winter. The process of making such a burger would take nearly a year, and would inherently involve omitting some core cheeseburger ingredients. It would be wildly expensive-requiring a trio of cows-and demand many acres of land. There's just no sense in it.

A cheeseburger cannot exist outside of a highly developed, post-agrarian society.