In a large bowl, whisk the milk, sugar, and vanilla together until the sugar dissolves. Pour into the bowl of an ice cream maker.
Layer cubed ice and rock salt around the ice cream bowl. (More salt will help the ice cream freeze faster.)
Secure lid on top of the ice cream bowl. Process for 20-30 minutes or as instructed for your specific ice cream maker, adding more ice and salt as needed.
Enjoy immediately as soft serve ice cream, or place in a freezer safe container and freeze 2-3 hours for a stiffer ice cream.
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Notes
NOTE: Since this is not a custard based ice cream, the texture is more like Italian ice. Think of it like powdery snow that melts in your mouth with the creamy taste of sweetened milk.NO ICE CREAM MACHINE: Pour the mixture into a shallow freezer-safe dish and put it in the freezer. Stir every 2-4 hours once ice crystals form. Tip: Use a fork or potato masher to scrape and fluff the ice cream mixture once it starts to solidify.*Half & Half (or half milk and half heavy cream) works well too.