Step 1

Heat the cream. Add the heavy cream and milk to a saucepan over medium heat. Whisk occasionally until it just starts to simmer with bubbles along the edges, then remove from the heat.

Step 2

Temper the eggs. Whisk the egg yolks in a medium bowl. While continuously whisking, very slowly pour half of the hot cream mixture into the bowl. Don't pour too fast or the eggs will curdle. Return the tempered egg mixture to the saucepan and stir together over medium-low heat for 1 to 2 minutes, or until the custard is slightly thickened. Turn off the heat.

Step 3

Add the chocolate. Add the chopped chocolate, espresso powder (if using), and salt to the custard. Let the chocolate melt for a minute, then whisk until it's completely smooth.

Step 4

Strain the mixture through a fine mesh strainer into a separate bowl (or measuring bowl with a pour spout), to remove any clumps and bubbles.

Step 5

Pour and chill. Pour the custard into six 4-ounce ramekins and refrigerate until chilled, about 2 hours.

Step 6

Serve. When ready to serve, let the pots de crème stand at room temperature for 15 minutes, to soften slightly. Garnish with whipped cream and chocolate shavings.