2 cups heavy whipping cream
2 cups half-and-half
1/2 cup sugar
2 teaspoons vanilla
1 bag of ice (crushed is recommended, but I’ve always used cubes)
2 cups coarse salt (I used kosher salt, and it worked great)
8 quart-sized zip bags
8 gallon-sized zip bags

Mix the first 4 ingredients together in a bowl or pitcher that pours. Place 1 cup in a quart-sized bag, squeeze all the air out of the bag and seal. Place bag into another quart sized bag, squeeze air out and seal. Repeat three more times to make 4 servings (uses up all the mix). Divide the bag of ice between 4 of the gallon bags. Add 1/2 cup of coarse salt to each bag. Place 1 quart bag of cream into each ice bag. Seal ice bag (no need to get air out).
Place dish towels around the bags to protect hands from cold and shake for 5 minutes. Remove from bag. Add favorite toppings and eat! If ice cream does not become solid after 10 minutes, add more ice and salt to the outer bag and shake again for 5 minutes.
Safety note: Use a towel or wear gloves. It’s very cold!