I can’t stop eating this croissant. Even though I just had lunch. And two desserts. Arthur Haynes is that brilliant with French pastry, his hand-rolled jewels of butter and air taking a minimum of 12 hours to allow the perfect chill on the dough. But baking is not the main attraction at his new Henderson dessert spot. It’s the 160-liter tank of liquid nitrogen, or rather, the fantastical confections it creates.

Hence the name, 346 Patisserie, as liquid nitrogen’s freezing point is -346. Arthur started working with it back in New York, where he graduated from the French Culinary Institute.

“It freaked me out a little bit, this evaporating cloud of liquid that kind of runs at you,” he says, calling his appreciation for its properties “an arranged marriage, almost. An interest became a passion.”

Having lent his skills to pastry teams at NYC dining heavies like Bouchon Bakery and Daniel, Arthur had the right stuff to serve in the Bellagio kitchen, though the pace and scale of the operation floored him. “On a slow day you’re doing 3,000 people at the buffet. It blows my mind,” says the chef, whose wife Amber was in full support of launching an independent, neighborhood shop. With her hospitality background and his culinary abilities, they did just that at the end of January.

The space is all white walls and checkerboard tiles, nothing distracting from the jars of rustic cookies, marshmallows and macarons and the case of gelatos, ice creams and sorbets. Flavors change frequently, and this day they range from chocolate anise to Szechuan pepper, lychee to a tasty pairing of olive oil and balsamic. Amber explains that she and Arthur have tested spin speeds to find ideal creaminess for the whole flavor catalog, which is expanding thanks to customers offering up everything from horchata to barbecue spices as inspiration. If a flavor is picked, the customer gets a free pint and credit inside the case.

But why eat plain old ice cream when you could top it with shattered chocolate mousse? Pouring rich mousse from a whipped-cream decanter into a bowl of extreme coldness, Arthur uses a metal cup to stir and shatter it as it freezes. The pieces look almost like moon rocks, porous and still wreathed in a fine nitrogen mist as I dip my spoon, ever so gingerly. But any fear melts away with the dessert, which tastes familiar. And awesome. And that’s the idea—new experiences with flavors we already know and love.

That means some kind of frozen cinnamon roll made with high-protein flour and yeast (“It almost acts like a bread”), though Arthur figures he’ll be perfecting that recipe for another few months before it’s ready. Despite the mystique of his method, he says he’s no mad scientist, reiterating that his liquid-nitrogen-aided desserts are as much about flavor and texture as his traditional tarts. “It’s just another technique.”

He uses it to freeze whole raspberries that he then pulverizes into a powder topping that turns into juice as it warms. Or to fortify spheres of toasted-marshmallow ice cream enrobed in marshmallows that he perfectly caramelizes with a torch. I watch him make this mutant s’more and then eat it in two bites, the layered taste of burnt sugar and morphing mouthfeel as the marshmallow meets the sphere’s cold, cold center, a truly different experience.

“It’s either gonna be the worst thing in the entire world, or it’s gonna be the best thing,” Arthur laughingly says of his creative process, though it’s hard to imagine anything un-delicious coming out of his kitchen. The macarons are textbook. The rose marshmallows are clouds of sweet perfume. And those croissants ... I had another one for dinner.

346 Patisserie 90 S. Stephanie St. #150. 11 a.m.-9 p.m. (closed Wednesday).