Vanilla Bean Soufflé

Wrap a 25-by-8-inch piece of parchment paper around the outside of a 7-by-4-inch soufflé dish to create a collar. Secure it with a 36-inch-long piece of kitchen twine.

In a small saucepan over medium heat, scald the milk, bringing it to just under a boil; reduce the heat to low. With a paring knife, cut the vanilla bean in half lengthwise. With the tip of the knife, open the pod to expose the seeds and scrape the seeds into the milk. Add the pieces of the pod and stir; keep warm.

In another small saucepan over low heat, melt the butter and whisk in the flour until smooth. Cook, whisking constantly, for about 1 minute. Remove the pieces of pod from the milk and discard the pod. Gradually add the milk to the butter-flour mixture, whisking constantly until smooth. Increase the heat to medium-low and cook, stirring constantly until the mixture is thickened, 4 to 5 minutes. Remove from the heat.

Position a rack in the lower third of an oven and preheat to 350°F.

In a large bowl, combine the egg yolks and salt, and whisk until the mixture is thick and light in color. Gradually add the superfine sugar, whisking until the sugar is dissolved. Gradually stir the milk mixture into the yolk mixture until fully incorporated and smooth. Refrigerate the sauce for at least 15 minutes.

In a copper beating bowl or mixing bowl, using a balloon whisk, beat the egg whites to soft peaks. (When the whisk is lifted straight out of the bowl and inverted, the whites should remain standing upright, with just a slight bend at the tip.)

Remove the vanilla sauce from the refrigerator and stir in the cognac. Add about 1 cup of the egg whites and stir until smooth. Carefully fold in the remaining whites. Immediately pour the soufflé mixture into the soufflé dish. Bake until the top is golden brown and the soufflé is almost double in height, 45 to 50 minutes. Dust with confectioners' sugar and serve immediately.