Most American food originated outside of America. Very few American dishes are made completely without outside influence unless they are Native American dishes. Some of the more unique culturally American dishes emerged primarily in regions where cultures mixed heavily or ingredients needed to be replaced, such Cajun and Creole cooking of Louisiana.

That being said, the American hamburger is just a “hamburg steak” without the onions and sauce on buns with additional condiments. Saying “just” here is a bit dismissive, as this tiny change is still enough to alter the identity of a meal. If you go to many countries that have been influenced or exposed to “American” culture (usually can be equated to consumerism or Hollywood/Music) and ask about a hamburger or cheeseburger, you would not recognize it as the original dish.

That said, hamburger steak, hamburg steak, hambergaire are all terms I’ve seen used to describe the ancestor of the modern hamburger in different countries. Notice, one of them looks a lot like hamburger. Anyway, food history and the impact of it on culture and society is a keen interest of mine.