The Necessary Ingredients

• Ice cream in a bag, whether it's chocolate or another flavor, needs only a few essential ingredients. In addition to chocolate milk, you will also need a little bit of sugar. The usual ice cream in a bag lists vanilla extract, which is optional. If the chocolate milk is extremely thick and rich, the extract will not really add anything flavor-wise. You will also need some salt -- most recipes call for rock or kosher salt, but table salt will do in a pinch.

Tools of the Trade

• The name "ice cream in a bag" is a bit deceptive because multiple bags are actually needed -- three, to be on the safe side. Resealable plastic bags work the best because they are the most secure. Two of the bags needed are the smaller sandwich or pint-sized ones, and the other is a gallon bag. The most important of all the tools needed is ice, and either cubed or crushed will do. Also, you will need a dishtowel to protect your hands when you actually start making the ice cream.

Mix It Up

• The actual process of making the mixture for ice cream in a bag is both quick and simple. Fill one of the pint-sized plastic bags with a mixture of 1 cup of chocolate milk for every 1/2 tablespoon of sugar. Press the excess air from the bag, then seal it. Place the sealed bag into the other pint-sized bag, press the excess air from that bag, then seal that one as well for extra protection.

Shake It Up

• Fill the larger bag with a couple of cups of ice -- up to about 4 cups -- then add 1.5 tablespoons of salt for every cup of ice. Place the smaller bags into the larger bag, press the excess air out, then seal the large bag. Cover the bags with a dishtowel, then shake the bag for about five to eight minutes, or until the chocolate milk and sugar mixture has condensed into ice cream. Remove the bag with the ice cream from the other two bags, then eat it straight from the bag.