Chill a 9x5x3 metal-loaf pan or any freezer-proof glass container of the same size.
Whisk dulce de leche and sea salt in a bowl. Set aside.
Whip the cream on medium-high speed until firm peaks form (about 2 minutes).
Fold about a cup of the whipped cream to the dulce de leche to lighten it then fold this into the whipped cream until well-combined.
Transfer into the chilled container and freeze, covered until solid.
Serve with your favorite topping or in a cone.