In a mixing bowl, whisk together the heavy cream, whole milk, granulated sugar, vanilla extract, and salt until the sugar is dissolved.

Pour the mixture into a freezer-safe container and freeze for at least 4 hours or until solid.

Once the base is frozen solid, remove it from the freezer and let it sit at room temperature for about 5 minutes.

Place the frozen base into the Ninja Creami bowl and process according to the manufacturer's instructions until creamy.

If using, add your optional mix-ins and process again briefly to combine.

Scoop the ice cream into bowls and enjoy immediately, or store in the freezer for later.