9 ounces high-quality semisweet chocolate, chopped
1 1/2 cups whole milk
1 1/2 cups heavy cream
6 large egg yolks
5 tablespoons granulated sugar (add an extra tablespoon if using bitter chocolate)
1/4 teaspoon salt
1 tablespoon confectioners' sugar
Place the chocolate in a blender. Whisk the milk, 1 cup cream, egg yolks, granulated sugar and salt in a heavy-bottomed medium saucepan over medium heat. Cook, stirring constantly with a heatproof spatula, until the mixture is thick enough to coat the spatula and almost boiling, 5 to 6 minutes.
Immediately pour the milk mixture over the chocolate in the blender. Cover and hold the lid with a thick kitchen towel; blend until combined and smooth, stopping to scrape down the sides of the blender as needed. Divide the chocolate mixture among ramekins or small cups and refrigerate until set, about 2 hours.
Whip the remaining 1/2 cup cream and the confectioners' sugar with a mixer or in the blender until soft peaks form. Top the chilled pots de creme with whipped cream.