1 tablespoon granulated sugar
1/2 cup milk or half-and-half
1/4 teaspoon vanilla extract
6 tablespoons rock salt
1 pint-size zip-type plastic bag
1 gallon-size zip-type plastic bag

Fill the large bag half full of ice, and add the rock salt. Seal the bag.

Put milk, vanilla extract, and sugar into the small bag, and seal it.

Place the small bag inside the large one and seal again carefully.

Shake until mixture is ice cream, about 5 minutes.

Wipe off top of small bag, then open carefully and enjoy!