If a British doughnut is made from dough, what is used to make an American donut?

Homer Simpson told me they're made of d'oh.

Americans do spell them "doughnuts" too, but "donut" is a clear Americanism. The difference is in terminology only. It seems that various misspellings and shortenings have been in use since the recipes were written down (including "dow nut").

In one of the earliest references, Washington Irving described them as "balls of sweetened dough." The original donuts were nut-shaped with no hole - i.e., what we now call donut holes. You may thus make the argument that the modern toroidal donut is described by the absence of this nut, i.e., donuts are made of hole.

https://en.wikipedia.org/wiki/Doughnut