Cream with sugar and air whipped in, then frozen.
A fine example of words failing to do justice to a concept.
The DeadTree edition of www.sciam.com, many moons ago, listed the following recipe (IIRC):
Put on a pair of oven mits, and get a big steel spoon ready.
Pour the liquid nitrogen slowly into the mix, whipping at it with the spoon.
When the cloud of condensed environmental water vapor clears, you have instant IceCream.
-- PhlIp