Prepare the chocolate: Place the chopped chocolate in a heatproof bowl. Set aside.

Heat the cream and milk: In a medium saucepan, combine the heavy cream, whole milk, and sugar. Heat over medium heat, stirring occasionally, until the mixture is just about to simmer (but do not bring it to a boil).

Temper the eggs: In a separate bowl, whisk together the egg yolks. Slowly pour a small amount of the hot cream mixture into the egg yolks, whisking constantly to prevent the eggs from scrambling. Gradually add the rest of the hot cream mixture into the egg yolks, continuing to whisk.

Cook the custard: Pour the egg and cream mixture back into the saucepan. Cook over low heat, stirring constantly, until the custard thickens slightly and coats the back of a spoon (about 5-7 minutes). Do not let it boil.

Add chocolate: Pour the hot custard mixture over the chopped chocolate. Stir gently until the chocolate is completely melted and the mixture is smooth and silky.

Strain the custard: To ensure a smooth texture, pour the custard through a fine mesh strainer into a clean bowl to remove any bits of cooked egg.

Chill: Divide the chocolate custard into individual serving cups or ramekins. Cover with plastic wrap and refrigerate for at least 2-3 hours or until set (overnight is best).

Serve: Once set, serve the pots de crème chilled, topped with a dollop of whipped cream and a sprinkle of shaved chocolate or cocoa powder, if desired.