Thermador shows you the secret to this decadent chocolate delicacy.
For the Soufflés
2 tbsp. sugar for the ramekins
8 oz. bittersweet 70% dark chocolate, finely chopped
1 tbsp. unsalted butter
1/3 cup milk
3 large eggs, yolks separated, at room temperature
1 large egg white, at room temperature
1/8 tsp. cream of tartar
1/3 cup sugar
8 6-oz. ramekins
For the Topping
1 cup heavy cream
1/2 tsp. pure vanilla extract
1 tbsp. powdered sugar for dusting (optional)
If you are baking the soufflés right away, position a rack in the lower third of the oven and preheat to 375°F. Butter the ramekins and sprinkle with sugar. Place the chocolate, butter and milk in a large heatproof bowl, then place the bowl in a large skillet of barely simmering water. Stir the mixture until the chocolate is melted and the consistency is smooth. Remove the bowl from the water bath and whisk in the egg yolks. (Don't worry if the mixture stiffens slightly or is less than perfectly smooth at this point.) Set aside.
In a medium bowl, beat the egg whites and cream of tartar with an electric mixer on medium speed until soft peaks form when the beaters are lifted. Gradually sprinkle all of the sugar and beat at high speed until the whites are stiff but not dry. Fold one-quarter of the egg whites into the chocolate mixture to lighten it, then fold in the remaining egg whites.
Divide the mixture evenly among the prepared ramekins, filling each three-quarters full. (The soufflés can be prepared to this point, covered, and refrigerated for up to two days. Bake directly from the refrigerator.) Place the soufflés on a cookie sheet. Bake until they rise and crack on top, so that a wooden skewer inserted into the center emerges moist and gooey. Bake about 14 to 16 minutes, or a minute or so longer if the soufflés have been refrigerated.
Meanwhile, make the topping: beat the cream with vanilla and sugar until it holds a soft shape (or stiffer, if preferred). Transfer to a serving bowl and refrigerate until ready to serve. When done, remove the soufflés from the oven and serve immediately, with a little powdered sugar sifted over the top if desired. Add whipped topping.