Preheat oven to 300 degrees.
Spray 8 demitasse cups with Pam. (should hold at least 3 ounces each to give a little room at the top)
Line a 9x13x2-inch casserole dish with a folded kitchen towel. Set aside.
Place chocolate in a glass bowl. Bring cream, milk, and a pinch of salt just to a boil in a small heavy saucepan. Pour over the chocolate in the bowl and whisk until the chocolate is melted and the mixture is smooth.
In a separate bowl, whisk together egg yolks, sugar, and a pinch of salt.
Then add the warm chocolate mixture to the egg mixture in a slow steady stream, whisking constantly until well incorporated. Pour custard through a sieve into a glass container, to eliminate any lumps, and cool for about 15 minutes, stirring occasionally.
Place ramekins on top of the folded towel in the 9x13 baking dish. Divide the chocolate custard evenly between ramekins, then fill the baking pan with water just halfway up the sides of the ramekins. Cover the baking dish tightly with foil.
Bake until custards are set around the edge, but still a little jiggly in the center, approximately 35 to 40 minutes.
Transfer ramekins to a wire rack to cool, uncovered.
Chill, covered, for at least three hours or overnight, before serving. Custards will become very firm as they chill. These will store in an airtight container for up to a week in the refrigerator. When ready to serve, garnish each pot de creme with a dollop of whipped cream and top with chocolate shavings.