In a large mixing bowl, whisk together the sweetened condensed milk, vanilla extract, and salt until well combined.

In a separate bowl, using a hand mixer or stand mixer with a whisk attachment, whip the cold heavy whipping cream on low speed, gradually increasing to high, until stiff peaks form.

Gently fold half of the whipped cream into the sweetened condensed milk mixture until just combined, then fold in the remaining whipped cream, being careful not to deflate the mixture.

Transfer the mixture into a 9x5 inch loaf pan, smoothing it into an even layer. Cover the surface directly with plastic wrap to prevent ice crystals from forming. Freeze for at least 8 hours, or overnight, until firm.