1155 Pontiac Avenue (just north of I-95 exit 14)
Open 7 days, 5am to 1am
except Fri, Sat open until 2am
hours after 11:30pm are drive-through only
You know the drill: incomparably good doughnuts, lousy coffee. Free hot-off-the-line donut to anyone who makes it through the (fairly quick) line today.
I don't think anyone there was buying in units of less than a dozen. I bought six (dozen that is).
Oh, and Providence's rush hour is a cakewalk compared to Boston's.