These exist in the US, but they're called black and white cookies. According to Wikipedia they may have been created in New York by Bavarian immigrants. But it's unclear if the confection's origin is German or American.

> These exist in the US, but they're called black and white cookies.

Most images of Amerikaner, like that on Wikipedia [1], are potentially misleading because they only show the upper side, so it looks like a cookie with frosting. But in actuality, the dough is not flat and evenly distributed like in a cookie, but gets much thicker in the center, see e.g. [2]. Not like a cookie at all.

[1] https://de.wikipedia.org/wiki/Amerikaner_(Geb%C3%A4ck)#/medi...

[2] http://4.bp.blogspot.com/-J6qYwRqgE6M/T76gn5d3XMI/AAAAAAAAA6...

"Ich bin ein Amerikaner."

And when Kennedy said "Ich bin ein Berliner", he was certainly not referring to the pastry (a jam-filled doughnut, though spheroidal instead of toroidal) known in most of Germany as "Berliner" but known in Berlin as "Pfannkuchen", which in the rest of Germany just refers to a pancake.