Bittersweet Chocolate Soufflé

1. Prepare Oven and Soufflé Dish

Remove any wire racks from the oven and place a baking sheet on the oven floor. Preheat the oven to 400 degrees Fahrenheit. Coat the interior of the soufflé dish with a dab of softened butter, then sprinkle granulated sugar to cover the surface, shaking out the excess.

2. Melt Chocolate and Butter

Combine the chopped bittersweet chocolate with a stick of softened unsalted butter in a microwave-safe bowl or over a pot of gently simmering water, stirring frequently until both are melted and smooth.

3. Combine Yolks and Chocolate Mixture

Whisk the egg yolks and a pinch of fine sea salt into the melted chocolate mixture, ensuring it's well combined and smooth.

4. Whip Egg Whites

With an electric mixer, beat the egg whites with the cream of tartar until they reach soft peaks. Gradually add the remaining granulated sugar as you continue to beat until stiff peaks form; the mixture should be glossy and hold its shape when the beaters are lifted.

5. Fold Egg Whites into Chocolate

Gently whisk a quarter of the egg whites into the chocolate mixture to lighten it. Fold the rest of the egg whites into the chocolate mixture delicately until no white streaks remain. Transfer the airy batter to the prepared soufflé dish.

6. Bake the Soufflé

Run your thumb around the inside edge of the dish to create a ¼-inch space between the soufflé mixture and the dish. Place the soufflé on the baking sheet in the oven and immediately reduce the temperature to 375 degrees Fahrenheit. Bake for about 25 to 35 minutes, until it has puffed up and the center jiggles slightly when nudged.