Fill the large container about half full with crushed ice and add about 6 tablespoons of rock salt to the ice. Seal the plastic jar and shake the ice and salt for about five minutes. *You may need to wear your gloves when you’re handling the jar. If you’re curious as to why you have to wear gloves, measure the temperature of the mixture with a thermometer. The rock salt and ice mixture gets down to about 14º F (-10º C)
Use a 1 quart-sized, zipper-lock bag to mix the following ingredients: 1/2-cup of Half & Half, 1/2-cup tablespoon brown sugar, 1 teaspoon vanilla extract (optional for flavor).
Seal the bag tightly, allowing as little air to remain in the bag as possible. (Too much air left inside may force the bag open during shaking.) Place the sealed bag inside the other quart-sized 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.
Place the two bags inside the container with the ice and seal the container.
Shake, rock, roll, and mix that can! Your ice cream should be ready after about 15-20 minutes. Once mixed, remove the inner bags from the jar and rinse them well with water. You don’t want any salt water accidentally getting into your ice cream.