Liquid Nitrogen Ice Cream
Why liquid Nitrogen (LN2)?  Is it a gimmick?  What about rock salt? 

When ice cream is made, the whole trick is to minimize the formation of ice crystals.  Liquid Nitrogen is 320°F below zero or -196°C; which can freeze alcohol and about anything else.  When using it to make ice cream, you can freeze a quart of ice cream in 2-3 minutes.   This fast freezing process creates tiny ice crystals, making a silky smooth ice cream like no other.

When using liquid Nitrogen as a freezing medium; it allows you to make smaller batches of ice cream, even custom flavors for an ice cream party, each guest gets there favorite flavor and is involved in the process.

Serves 4
Ingredients for Ice Cream Base:

2CupOrganic Cream, un-homogenized
1CupOrganic Half & Half, un-homogenized
3/4    Cup       Organic Sugar
3Each      Organic Egg Yolks
1Pinch     Sea Salt

4-5    Quarts    Liquid Nitrogen*

For Flavorings Ideas:

Chocolate Espresso Ice Cream

1/2    Recipe  Ice Cream Base
1/4    Cup       Coco Powder, Valrohna
1Shot      Espresso, freshly brewed
1Tablespoon   Nutella, Chocolate Hazelnut Spread

Vanilla Ice Cream

1/2   Recipe   Ice Cream Base
1Tablespoon   Vanilla Extract
Directions:

To make Ice Cream Base:

In a medium sized pot, combine the cream, half & half and sugar over medium heat.  Stir to dissolve the sugar, and bring mixture to 170 degrees and remove from heat.  In a separate bowl, add egg yolks and whisk for a minute.  Whisk in 2 ounces of hot cream mixture to the yolks, to temper them.  Add another 2 ounces, whisking to prevent cooking the mixture.  Pour yolk mixture back into the remaining cream mixture, whisking to incorporate.  Strain mixture through a fine sieve into another bowl, to remove any cooked yolk.  Add flavorings if you wish, or use your own flavoring ideas.  Chill mixture in either a ice bath or refrigerator, until mixture is cold (around 36°).   

To make Ice Cream with Liquid Nitrogen:

Place your cooled flavored ice cream base into the bowl of an electric mixer fitted with a whisk attachment.  Turn on the mixer for a few minutes to whip some air into the mixture.  Then turn the mixer off and carefully add about 2 cups of liquid Nitrogen with a stainless steel ladle or by pouring slowly into the bowl of your mixer, turning the mixer on low after it has been added.  Repeat this same procedure until the ice cream has set, usually with about 6-8 cups of liquid Nitrogen per half batch.  Serve immediately.
Chocolate Espresso Ice Cream
Vanilla Ice Cream
Caution when working with Liquid Nitrogen:

Sharp knives, hot oil, boiling water, slippery floors are all dangerous items in a kitchen, as is Liquid Nitrogen. When working with a substance that is -320 degrees F, one must take extra care in using this liquid.  Special gloves, goggles or a face shield are highly advised when working with this medium.  Exposure to Liquid Nitrogen can cause freezer burn and frost bite resulting in tissue damage, spitting and spattering that can damage eye injury and possible suffocation (if working in an area that is not well ventilated).  
*Liquid Nitrogen:

Liquid Nitrogen is rather cheap, available at welding supply shops, Praxair and other gas outlets for $0.50 to $1.00 a liter.  To transport the Liquid Nitrogen is different.  A standard cooler or container will not work, as it will freeze.  A Dewar is a specially made thermos if you will that will hold between 5-10 liters of Liquid Nitrogen.  The lid on a Dewar is made to let the evaporation escape out the container, to dismiss the issue of liquid to gas expansion, causing an explosion by accumulated pressure.  Dewars can be found at Lab Supply companies and eBay.  The cost can range from $250 – 600.