Ingredients and equipment:
1 sandwich-size ziplock bag
1 gallon-size ziplock bag OR large glass jar OR large coffee can
3 cups ice
⅓ cup kosher or rock salt
½ cup whole milk
½ cup heavy cream
¼ cup sugar
2 tsp. corn syrup
1 tsp. milk powder
½ tsp. vanilla extract (or to taste)
⅛ tsp. salt (or to taste)
1. Mix or whisk together milk, cream, sugar, corn syrup, and milk powder. Add vanilla and salt to taste.
2. Fill the gallon-size ziplock with three cups of ice and kosher/rock salt.
3. Pour the milk-and-cream mixture into the sandwich-size ziplock, seal it tightly, getting as much air out of the bag as possible, and put it inside the gallon-size ziplock, jostling it a little so that it’s surrounded by the ice and salt. Seal the large bag.
4. Shake vigorously for 15 to 20 minutes, or until the mixture has reached the desired texture. Remove the smaller bag, serve, and enjoy.