01 - Place heavy cream, granulated sugar, vanilla extract, and salt into a clean 16-ounce mason jar.
02 - Secure the lid tightly onto the mason jar.
03 - Shake vigorously for 4 to 5 minutes until the mixture thickens and doubles in volume, ensuring it coats the back of a spoon.
04 - Gently fold in desired mix-ins using a spoon.
05 - Place the sealed jar in the freezer for at least 4 hours, allowing the ice cream to firm up.
06 - Remove the jar from the freezer, let sit at room temperature for 5 minutes, then scoop and serve directly from the jar or in a bowl.