Ten days ago, they started with making about eight a day. That's ballooned to more than 100 and multiple batches a day.
"We did one. And had a few requests for them so made some more ... now they're selling out in two hours," Mr Kinvig said.
The basic dough is roughly a quarter butter and three quarters flour with some yeast, salt and honey. Mr Kinvig then rolls and folds it over and over until there are 26 delicate layers.
The doughnut-shaped pastries, sold for $5.50 each, are cut out, deep-fried until they're a golden brown and rolled in sugar.
Yesterday, there were six flavours on offer - lemon curd and coconut, chocolate and macaroon, chocolate, peanut butter and pumpkin seeds, dehydrated orange, chocolate, and maple and pecan.
The cafe changes the flavours daily and Mr Kinvig said they'd probably keep producing the pastries until everyone's making them.
"At the moment, for me, it seems like it's seek and destroy. People will start to get over them."
But for now it doesn't seem likely.
The Herald's verdict:
As a long-time admirer, first-time trier, the cro-not was everything I dreamed it would be. Hours of my time have been lost scrolling through images on Buzzfeed of the tasty treats being gently deep-fried, softly rolled in sugar then slowly iced.
The photographer and I were given a lemon curd and coconut one to share. It was the opportune moment to join the rest of the internet and share my #cronut #bliss experience on Instagram and gloat to my friends that my lunch was better than theirs. But with my fingers trembling with excitment for the first bite, the phone slipped and the treat dropped from my hands. But like a mother protecting her child, my instinct kicked in and I saved the delicate pastry with only a smudge to show for its near-death drop. It was light, sugary and much less stodgy than a doughnut and the lemon curd perfectly complemented the fluffy pastry. I'll definitely be back for one of every flavour.
What is a cronut?
A mixture of a croissant and a doughnut that is only available in the United States, thanks to a strict patent law by the Dominique Ansel Bakery in New York. However, the recipe has been mimicked by bakers around the world with slight variations on the name - a bakery in Britain calls their version CroDoughs. Some black market replicas are being sold for a mere $100 a pop.