1/2 cup milk
1/2 teaspoon vanilla
1 tablespoon sugar
4 cups crushed ice
4 tablespoons salt
2 quart-size Ziploc bags
1 gallon-size Ziploc freezer bag
1 hand towel ( or gloves or potholders) to keep fingers from freezing
Mix the milk, vanilla and sugar together in one of the quart-size bags. Seal tightly, allowing as little air to remain in the bag as possible. Place this bag inside the other quart-size bag, again leaving as little air inside as possible and sealing well. By double-bagging, the risk of salt and ice leaking into the ice cream is minimized. Put the two bags inside the gallon-size bag and fill the bag with ice, then sprinkle salt on top. Again let all the air escape and seal the bag. Wrap the bag in the towel or put your gloves on, and shake and massage the bag, making sure the ice surrounds the cream mixture. Five to eight minutes is adequate time for the mixture to freeze into ice cream.