Burn the Churn

The conceit of making ice cream is a time-consuming one--or at least, it used to be. Thanks to liquid nitrogen, kitchens are doubling as science labs (again): When chefs add the stuff to a cream base, the mixture immediately freezes up, providing instant frozen treats.

Sub Zero began as a single storefront in Orem, Utah; its liquid-nitrogen concoctions proved so popular that it now has eight locations in Utah and Idaho, with future stores planned for Arizona. The experiments continue past liquid nitrogen: The Sha'Blam sundae blends citric acid into Mountain Dew ice cream for an entertaining fizzy chemical reaction.

Lulu and Mooky's in Manhattan enhances its ice cream with organic fruit, herb extracts and purees (enough to make a purported 10,000 combinations, the owners say) such as pear, kiwi, pumpkin-spice--even rosemary and cayenne. Choose that combination wisely!

In addition to the standard ice cream and yogurt, Chicago's iCream offers pudding--thickened by the nitrogen--as a potential canvas for your favorite flavorings and toppings in its Wicker Park café. The burnt-sugar flavor makes for a nostalgic bespoke dessert.

In suburban Las Vegas, Atomic #7 has every frozen base covered. The vegan-friendly spot is particularly sensitive to the restricted diet, offering frozen treats made from organic cream, soy-, almond-, rice-, coconut-, lactose-free milk or yogurt with sweeteners like agave and truvia.