Fwiw I'm not American and get a good laugh out of /r/shitamericanssay sometimes, but I can think of: 'tex-mex', California roll sushi, deep dish pizza, bagels as sandwiches (I think? Not the bagel itself, but using it as a bun), different uses of okra than I'm aware of elsewhere like stewed/chowders/soup, some of that stuff in the south in general actually spicy shellfish chowders etc. I think there's a good argument is evolved from what came before it elsewhere.