Preheat oven to 300°F (150°C) and place rack in the middle.

Simmer 8 cups of water in a large saucepan.

Arrange ramekins in a roasting pan.

Prepare a small bowl of water and a pastry brush.

Heat cream and milk in a saucepan until boiling, then remove from heat.

Combine sugar and 2 tablespoons water in a heavy-bottomed saucepan.

Bring to a boil, stirring until sugar dissolves.

Continue cooking without stirring, brushing sugar crystals with the pastry brush, until dark amber.

Remove from heat immediately.

Whisk in warm cream mixture slowly, starting with 1/2 cup, until combined.

Set aside.

Whisk egg yolks in a heatproof bowl until blended.

Slowly pour 1 cup of the cream mixture into the yolks while whisking.

Pour the cream-egg mixture back into the saucepan and whisk to combine.

Add chocolate and whisk until melted and combined.

Strain the custard through a fine-mesh strainer into a large measuring cup.

Divide the strained custard among the ramekins, filling them three-quarters full.

Add simmering water to the roasting pan to reach 1 inch up the sides of the ramekins.

Cover the pan tightly with aluminum foil.

Bake until the tops are darkened and almost set, about 1 hour (45 minutes for espresso cups, 25 minutes for candle holders).

Cool to room temperature on a wire rack.

Serve or refrigerate overnight.

If refrigerated, let sit at room temperature for 20 minutes before serving.