Whip the cold heavy cream in a chilled bowl until stiff peaks form, about 2 to 3 minutes.

Whisk the sweetened condensed milk, cocoa powder, vanilla, and salt together until smooth.

Fold the chocolate mixture gently into the whipped cream until no streaks remain. Transfer to a loaf pan, press plastic wrap onto the surface, and freeze for at least 6 hours.

Scoop the frozen ice cream into bowls and serve with a pinch of flaky salt if you like.