Unlike most chocolate soufflés, these are made without milk or starch. They are light yet moist, with an exceptional chocolate taste.
Preheat the oven to 375°F. Butter and sugar six 10- to 11-ounce ramekins (see About Dessert Soufflés) and arrange on a baking sheet.
Combine in a heatproof bowl:
8 ounces semisweet chocolate or bittersweet chocolate, chopped
6 tablespoons unsalted butter
2 tablespoons rum, coffee, or water
Set the bowl in a skillet of hot, but not simmering, water and stir until the mixture is smooth. Let cool for 10 minutes and then whisk in:
6 large egg yolks
Beat on medium speed until foamy:
6 large egg whites, at room temperature
Add and beat on high speed until soft peaks form:
Heaping 1/4 teaspoon cream of tartar
Gradually beat in:
1/2 cup sugar
Beat until the peaks are stiff but not dry. Using a large rubber spatula, stir one-third of the egg whites into the chocolate mixture, then gently but thoroughly fold in the remaining mixture. Divide the batter equally among the prepared ramekins and smooth the tops. Bake until risen and set, about 20 minutes. If you wish, after bringing the soufflé to the table, open a slit in the top of each soufflé with 2 forks held back to back and add:
Custard Sauce, or a white chocolate truffle or a dark chocolate truffle
The soufflés can be covered with plastic wrap and refrigerated for up to 24 hours before baking.
