Probably San Francisco's best doughnut shop, Bob's Donuts, is expanding for the first time in it 50+ years, opening a second location at Fulton and Baker streets.

The doughnut operation known for its divine glazed and old-fashioned doughnuts, not to mention its apple fritters, is moving into the space vacated by Chili Pies Baking Co. at 601 Baker Street. And it looks like the name will be Bob's On Baker.

Unlike most similar shops, Bob's operates 24 hours a day on Polk Street, and has for decades. As Eater reports, it's not yet known if the new location will try to do the same thing — odds are no, given the sleepier locale of Baker Street. But this is nonetheless fantastic news for lovers of good doughnuts who also hate going to upper Polk Street.

Opened in 1959 by a man named Bob about whom little has been recorded, Bob's gained notoriety under the ownership of Elinor Ahn, the longtime proprietor of the shop whose family bought the business from Bob in 1977. Ahn passed away in 2001, but she and her doughnut shop are immortalized in a 2003 song by Sun Kil Moon, a.k.a. longtime San Francisco lover Mark Kozelek. In the second verse of his song "Glenn Tipton," he sings, "I knew an old woman who ran a doughnut shop/ she worked late servin' cops./ Then one morning baby her heart stopped. / Place ain't the same no more / The place ain't the same no more,/ not without my friend, Elinor."

Bob's is now run by Elinor's daughter, Aya Ahn, and her son-in-law, and their twentysomething children. As Rachel Ahn, who grew up in the shop, told the Chronicle in 2016, "People ask who Bob is, and we tell them we’re all Bob."

Look for Bob's on Baker to open soon — though the exact date is still TBA.