Fill a small resealable bag with 1 cup half-and-half, 2 tablespoons sugar, and 1/2 teaspoon vanilla extract
Seal the small bag tightly, removing as much air as possible
Fill a larger resealable bag halfway with ice
Add 1/2 cup salt to the ice in the larger bag
Place the sealed small bag inside the larger bag
Seal the larger bag tightly
Shake the bag vigorously for 5 to 10 minutes
Wear gloves or wrap the bag in a towel while shaking
Check the small bag for thickened ice cream
Remove the small bag from the larger bag
Rinse off any saltwater from the outside of the small bag
Open the small bag and eat the ice cream immediately
Add toppings if desired, such as chocolate chips, sprinkles, or fruit