Whip the cold heavy cream on medium speed until stiff peaks form, 3 to 4 minutes.

In a separate bowl, stir together the sweetened condensed milk, peanut butter, vanilla, and salt. Fold a third of the whipped cream into the peanut butter mixture, then fold that back into the remaining whipped cream until no streaks remain.

Scrape the mixture into a 9×5 inch loaf pan, smooth the top, press parchment onto the surface, and freeze for at least 6 hours or overnight.

Let the ice cream soften at room temperature for 5 minutes, then scoop and serve.