The recipe was easy to prepare and the kids loved the interactivity of shaking the ice cream bags.  On the downside, the ice cream never got thicker than slightly solid so the kids didn’t love eating it until after it stayed in the freezer a couple hours.  Then I can vouch that it was absolutely delicious (though lots of work for a small amount of ice cream)!

Ingredients:
½ cup sugar
¼ teaspoon salt
1 cup milk
3 beaten egg yolks
1 tablespoon vanilla extract
2 cups chilled whipping cream
2 cups fresh strawberries and extra ½ cup sugar

Directions:

Put the sugar, salt, and milk into the top pan of a double boiler. Stir the 3 beaten egg yolks into the milk and sugar. Cook the mixture over boiling water until you can see bubbles forming around the edges of the mixture. The mixture is done when it is somewhat thick, and coats the spoon. Let the mixture cool to room temperature. When the custard has cooled, stir in the vanilla extract and the heavy whipping cream.

The fun part is about to begin. This is where having a bunch of kids to help is really nice. Fill a gallon size food storage zip-lock bag about one third full of ice cubes. Add a cup of salt. Zip the large bag closed, and wrap it in a towel to keep fingers from getting too cold. Make a bag for everyone (this recipe will make enough for three or four servings, and you can double or quadruple the recipe if you are having a party).

Now have each person squish the little bag around in the salt and ice, making sure that the ice contacts the little bag as much as possible, and that the little bag gets lots of kneading, to keep the ice crystals tiny, so the ice cream is very smooth.  The kneading stage takes 10 minutes. You can let the ice cream sit in the ice for another 5 minutes if you like harder ice cream, although continuing to knead it for the extra 5 minutes is also OK to do if you're having fun.

You will know the ice cream is done by feeling the mixture become a paste instead of a liquid. When you take the little bag out of the ice, wipe off the salt water, and then remove the outer bag carefully, so you don't get salt in the ice cream. The little bag will stand up in the bowl, because it is a frozen paste. You can spoon the ice cream into a bowl if you like, or just eat it out of the bag.

If you like strawberry ice cream, mash 2 cups of strawberries with a half cup of sugar, and add a half cup to each small bag before closing it up and putting it in the ice.

The result is an amazingly delicious homemade ice cream.

This full recipe can be found with pictures showing the process at: http://sci-toys.com/scitoys/scitoys/thermo/ice_cream/ice_cream.html