Do cops eat doughnuts, or donuts?

As I considered what sort of photo I ought to place at the top of my spanking-new blog, an image of a policeman eating a doughnut popped into my head.

Then my Undercover Copy Editor side piped up.

“Wait a second,” the small voice said. “Is that thing a doughnut, or a donut?”

When I checked my AP Stylebook smartphone app, I was pleased to see there was actually a “doughnut” entry. It even had a star next to it. The entry itself, however, was not stellar. It was disappointingly brief — no mention of the possibility my imaginary policeman might want to dunk his “donut” into a cup of coffee.

The Merriam-Webster Dictionary (online at least) notes:

Variants of DOUGHNUT
dough·nut also do·nut

The online Oxford Dictionary also slips in a parenthetical: (also donut).

Many dictionaries note that “donut” is an American (vs. British) English variant spelling for “doughnut,” but surprisingly enough … they have “donuts” in England, too.  You just wouldn’t want to eat them.
An idiot. A mild insult often used in the work places of southern England
-nuts, -nutting, -nutted3. (transitive) (informal) (of Members of Parliament) to surround (a speaker) during the televising of Parliament to give the impression that the chamber is crowded or the speaker is well supported

— Nadine Siak