AFTER all, they were originally oliebollen, so yes, Delft blue is allowed. The Dutch cooked them in America the way they had always made them at home, with raisins and pieces of apple. These were not there for grins. During the frying, the apple and raisins were heated to a boil, and that cooked the entire inside of the oliebol well-done.
Non-Dutch immigrants loved the Dutch oliebol. But over time, they increasingly omitted ingredients, which resulted in still half-raw dough inside. So they punched a hole in the middle: the dough nut.
Delft blue is very much justified. It tells Americans where their donut originally comes from.
