Place a medium-sized mixing bowl (3-4 quarts, metal or glass) in the freezer. If you are using a stand mixer, place the wire whisk attachment in the freezer with the mixing bowl. If you are using a handheld mixer, place the beaters in the freezer.

Line a 9x5 metal loaf pan (or a 9x5) with plastic wrap, then place the loaf pan in the freezer as well. Freeze the loaf pan, mixing bowl, and whisk (or beaters) for 30 minutes.

Add the sweetened condensed milk, ¾ cup Nutella, vanilla, and salt to a medium-sized mixing bowl (3-4 quarts). Whisk to combine.

Remove the mixing bowl and whisk or beaters from the freezer. Pour in the cold heavy cream. Beat the cream on high speed until stiff peaks form.

Gently fold 1 cup of the whipped heavy cream at a time into the sweetened condensed milk mixture.

Remove the metal loaf pan from the freezer. Evenly spoon the whipped cream mixture into the loaf pan. Cover with aluminum foil and place back in the freezer for 2 hours.

Remove the foil-covered loaf pan from the freezer. Dollop 3 heaping tablespoons of the remaining Nutella. Swirl with a knife to distribute the Nutella. Drizzle the remaining 1 tablespoon of Nutella. Cover the loaf pan with the aluminum foil and freeze for an additional 3 hours. (If your home is on the warmer side, you may need to increase the freeze time.) Remove the foil before scooping and serving.