Place 1/4 C of ice cream mixture into a small baggie
Seal the baggie completely.
Place the sealed baggie into a large baggie
Add 1/4 C rock salt and ~2Cs crushed ice.
Seat the large baggie.
Agitate (shake) bag for ~ 10 minutes. When the mixture sealed in the
inner small baggie is thickened, remove it from the large baggie, open
and dig in!