The steps for making homemade ice cream in a bag include mixing the cream and other ingredients, pouring the mixture into a small resealable freezer bag, pouring ice and salt into a larger bag, and placing the smaller bag into the larger bag. The last steps include mixing and massaging the bag until the cream mixture freezes, followed by transferring the ice cream to a bowl.
In a mixing bowl, combine 2 cups half-and-half, 2 cups heavy whipping cream, 1/2 cup white sugar and 2 teaspoons vanilla extract, stirring until the sugar dissolves. The mixture makes enough liquid for eight servings prepared individually. Place the mixture by 1/2-cup servings into resealable, pint-sized plastic bags. After squeezing out the excess air, double-bag each one. Gather enough gallon-sized plastic bags to accommodate each mixture-filled bag, and fill them half-way with crushed ice and coarse salt at a ratio of 4 cups salt for 1 large bag of crushed ice.
After placing the small bags in the larger bags of ice, squeeze out excess air, and seal them. Using thick gloves or mittens to protect against the below-freezing temperatures, gently shake and massage the bags for five to 10 minutes or until ice cream forms. Remove the small bags from the larger bags, and pour them into bowls for serving. Add syrups, sprinkles, crushed cookies or other ice cream toppings of choice, and serve immediately.