I have run across a curious essay, claiming that
a cheeseburger was so impractical, more than a century ago, that nobody would have though of it: lettuce is a cool-weather crop, tomatoes a summer crop, meat an autumn product. (He does not say impossible; "a time-traveller with an unlimited budget could have had one.")
There is severe dissent in the comments; I'm not sure myself. It Aside from the obvious, that cheese and tomatoes would not be found in the same place before 1492, I'm not sure the argument holds. (and I don't have tomato on cheeseburgers.) It may be useful to distinguish betw\een the Renaissance and the eighteenth century. But my friends know more about medieval food than I do.