Place the chopped chocolate into a medium heat-proof bowl.

In a saucepan, heat the heavy cream over medium heat until it just begins to simmer; do not let it reach a full, rolling boil.

Pour the hot cream over the chocolate and let it sit undisturbed for 2 minutes.

Whisk the cream and chocolate mixture gently starting from the center until it is perfectly smooth and glossy.

In a separate bowl, whisk the egg yolks, sugar, and salt together until the mixture is slightly pale.

Slowly temper the eggs by drizzling about one-quarter of the warm chocolate-cream mixture into the yolks while whisking constantly to prevent the eggs from scrambling.

Gradually incorporate the remaining chocolate liquid into the egg mixture.

Strain the custard through a fine-mesh sieve into a pitcher or measuring cup to ensure there are no stray bits of egg.

Divide the mixture evenly among the four ramekins.

Place the ramekins into the roasting pan and cover the tops of the ramekins tightly with aluminum foil to prevent a skin from forming.

Pour boiling water into the roasting pan until it reaches halfway up the sides of the ramekins.

Bake for 25 to 30 minutes. The custards are done when they are set at the edges but still have a slight, uniform jiggle in the center when you nudge the pan.

Remove the ramekins from the water bath, let them cool to room temperature, and then refrigerate for at least 3 hours before serving.