Bitcoin-themed cupcakes are one custom creation at Cups and Cakes Bakery in San Francisco. Shop owner Jennifer Longson accepts bitcoins as payment and has even brought cupcakes like these to bitcoin meet ups.   - 

You know the cupcake rage of the past couple of years? A cynic might even call it a bubble. Okay, keep that in your back pocket and think about bitcoins, the cyber currency that's been quite bubble-iscous itself this past month or so.

Roll them together and what do you get? A cup-cakery that takes bitcoins.

Jennifer Longson owns Cups and Cakes in San Francisco. Her husband works in the tech industry and was enthusiastic about bitcoins. In the retail store, she uses an iPad as her cash register, so it didn't take much to become bitcoin friendly.

"We just bring up the BitPay app and we type in how much they owe us. Up pops a QR code, and they scan it with their online wallet with their phone," Longson says. "And in about 30 to 60 seconds, it pops up that it's confirmed."

Initially Longson only had one or two bitcoin customers per month. Now it's up to three to five per week. She's not too worried about the volatility, as she is leaving the bitcoins where they are.

As for whether the cupcake bubble has burst, Longson is similarly optimistic.

"I mean, the first cupcakery opened like 15 years ago. Is that a bubble?" she asks. "My business is as good as usual, if not better."

She points out that unlike large chains like Crumbs that expanded quickly, her shop is small.

"It's just two employees, plus me."

Follow Kai Ryssdal at @kairyssdal