step 1 Preheat oven to 325 degrees F with baking rack in the center.
step 2 Bring 1 1/2 cups of water to a boil in a tea kettle or saucepan and keep hot. Place chopped chocolate in a medium-size bowl.
step 3 Combine the milk, heavy cream and cinnamon in a medium-size saucepan. Bring just to a boil over medium-high heat. Remove the pan from the heat and pour the mixture over the chopped chocolate in the bowl. Stir with a spatula until the chocolate melts and mixture is smooth.
step 4 Whisk together the egg yolks, sugar, vanilla and salt in a medium-size bowl until blended. Continue to whisk constantly, while slowly adding the warm chocolate mixture from Step 3 to the egg mixture until blended. Strain the combined mixture (custard) through a sieve (fine mesh, if you have one) into a 4-cup glass measuring cup or bowl.
step 5 Place 8 ramekins or oven-safe custard cups (4 to 6 ounces each) in a baking dish or roasting pan that is at least 3 inches deep. (Note: Instead of ramekins, you can use any ovenproof, nonmetal cups—like tea, espresso or demitasse cups made of glazed earthenware, porcelain or ovenproof glass.)
step 6 Pour the custard, in equal amounts, into the custard cups. Carefully pour the hot water into the baking dish or roasting pan, about halfway up the outside of the custard cups. Cover the roasting pan tightly with foil and poke a few holes in the top with a metal skewer or toothpick.
step 7 Carefully place the pan in the oven and bake for 30–35 minutes until the custard is set but still jiggles a little in the center when the side of the cup is tapped with a metal spoon.
step 8 Use tongs or oven mitt to remove the custard cups from the baking pan (be careful not to touch the water in the baking pan) and place on a cooling rack for about 30 minutes. Once cooled thoroughly, refrigerate at least 2 hours before serving.
step 9 Serve chilled, garnished with raspberries or sliced strawberries and lightly dusted with powdered sugar, if desired.