In a medium bowl, whisk together sweetened condensed milk, vanilla, peanut butter, and salt. Set aside.

In a large bowl, beat whipped cream with an electric mixer until stiff peaks form, approximately 2 minutes. Fold approximately 1 cup of the whipped cream into the peanut butter mixture until combined. Fold the peanut butter cream mixture back into the whipped cream until well combined.

Pour the mixture into a metal loaf pan. Dot with jelly on top randomly, then swirl the jelly into the ice cream base. Cover with plastic wrap and freeze for at least 5 hours before serving.