Position a rack in the middle of the oven and preheat to 300 degrees . Using a food processor, pulse 1 cup pistachios and 5 tablespoons sugar until finely ground.
In a saucepan, heat the cream, ground nut mixture, vanilla and salt over medium heat, stirring, until steaming, about 5 minutes. Remove from the heat, cover and let stand for 30 minutes; strain, pressing to extract any cream. Discard the nuts.
In a large bowl, beat the egg yolks, then whisk in the pistachio cream. Divide among four 1/2- to 2/3-cup ramekins set in a baking dish. Pour enough warm water into the pan to come halfway up the sides of the ramekins. Bake until the custards are set with a slight jiggle in the center, 45 to 50 minutes.
Remove the ramekins from the water bath. Let cool for 30 minutes, then freeze for 1 hour.
Just before serving, position an oven rack 2 inches from the broiler and preheat. Sprinkle the custards with the remaining 8 teaspoons sugar. Broil until browned, 3 to 5 minutes. (Alternately, use a kitchen torch to caramelize the sugar.) Chop the remaining 2 tablespoons pistachios and sprinkle on top.