Johnny Doughnuts In San Rafael Marin | Tasting Table San Francisco

You wouldn't expect to find mashed potatoes in your bismarck, but it's the secret behind the airy crumb and crisp exteriors of Craig Blum's yeasted, raised doughnuts.

At Johnny Doughnuts, which opened on the eastern edge of downtown San Rafael three weeks ago, Blum makes giant, puffy wheels ($2.50), bismarks ($3) and braids ($2.50) from a decades-old recipe unearthed after an exhaustive search. Blum says: "I had to go back to cookbooks from the 1920s."

Craig Blum, doughnut maker

Turns out most doughnut shops use prepackaged mixes. That's where the taters come in: You can taste their faint, welcome earthiness most clearly in the vanilla rounds, whose tops gleam with a translucent sugar glaze.

The other flavors change often. Chocolate sprinkles appear randomly. Sometimes, the Gravenstein apple fritter ($3) contains an extra swirl of caramel. On one visit, we picked up a raised twist covered in sweet-tart pineapple glaze and coconut curls; a week later, we demolished one with maple frosting and bourbon-spiked brown sugar. Gold stars for both.

Now that his Marin store is open, Blum's about to send a Johnny Doughnuts truck to San Francisco (check the Facebook page for dates and times).

Old-school recipe, new-school shop.