Center the rack in the oven and preheat to 325 degrees.
Heat ½ cup cream and the chocolate in the top of a large double boiler over hot water on moderate heat. Whisk and heat until the chocolate is melted and smooth.
In a mixing bowl, stir the egg yolks lightly to mix – do not beat until foamy. Heat the remaining 1-½ cups cream. Stir in the sugar and salt. Add the cream to the eggs, stirring constantly. Then stir in the chocolate mixture and the vanilla.
Return the mixture to the heat in the double boiler and cook, stirring constantly with a rubber scraper, until it starts to thicken.
Pour the mixture through a fine strainer into a pitcher. Then pour into individual ½ cup soufflé dishes; do not fill all the way. Place the cups in a shallow baking pan. Pour hot water to about half the depth of the cups. Place a cookie sheet over the top to cover the cups (or if you have used pot de crème cups, put their covers on)
Bake for 22 minutes. The usual test for baked custard is to insert a small, sharp knife halfway between the middle and the edge and when it comes out clean, they are done. However, with this recipe, if it comes out clean the pots are overdone. The custard will look soft, but it will become firmer as it chills. It is best if it is still creamy in the center when served.
Place on a rack to cool, then refrigerate a few hours.