Chocolate Soufflé

1. Adjust oven rack to lower-middle position and heat oven to 375 degrees. Grease 2-quart soufflé dish with 1 tablespoon softened butter, then coat dish evenly with 1 tablespoon sugar; refrigerate until ready to use.
2. Melt chocolate and remaining 4 tablespoons butter in medium heatproof bowl set over saucepan of barely simmering water, stirring occasionally, until smooth. Stir in liqueur, vanilla, and salt; set aside.
3. Using stand mixer fitted with paddle, beat egg yolks and remaining 1⁄3 cup sugar on medium speed until thick and pale yellow, about 3 minutes. Fold into chocolate mixture.
4. Using dry, clean bowl and whisk attachment, whip egg whites and cream of tartar on medium-low speed until foamy, about 1 minute. Increase speed to medium-high and whip until stiff peaks form, 3 to 4 minutes.
5. Using rubber spatula, vigorously stir one-quarter of whipped whites into chocolate mixture. Gently fold in remaining whites until just incorporated. Transfer mixture to prepared dish and bake until fragrant, fully risen, and exterior is set but interior is still a bit loose and creamy, about 25 minutes. (Use 2 large spoons to pull open top and peek inside.) Serve immediately.

To melt the chocolate using a microwave, heat it at 50 percent power for 2 minutes; stir the chocolate, add the butter, and continue heating until melted, stirring once every additional minute. Soufflé waits for no one so be ready to serve it immediately.

MOCHA SOUFFLÉ
Add 1 tablespoon instant espresso powder dissolved in 1 tablespoon hot water when adding vanilla to chocolate mixture.

INDIVIDUAL CHOCOLATE SOUFFLÉS
Omit 2-quart soufflé dish. Grease eight 8-ounce ramekins with butter and sugar. In step 5, transfer soufflé mixture to ramekins, making sure to completely fill each ramekin and wipe each rim with wet paper towel. Reduce baking time to 16 to 18 minutes.

MAKE-AHEAD INDIVIDUAL CHOCOLATE SOUFFLÉS
Omit 2-quart soufflé dish. Grease eight 8-ounce ramekins with butter and sugar. In step 3, bring sugar and 2 tablespoons water to boil in small saucepan, then reduce heat and simmer until sugar dissolves. With mixer running, slowly add sugar syrup to egg yolks and beat until mixture triples in volume, about 3 minutes. Whip egg whites as directed, beating in 2 tablespoons confectioners’ sugar. Stir and fold into chocolate base as directed. Fill each chilled ramekin almost to rim, wiping each rim clean with wet paper towel. Cover each ramekin tightly with plastic wrap and freeze until firm, at least 3 hours or up to 1 month. (Do not thaw before baking.) To serve, heat oven to 400 degrees and reduce baking time to 16 to 18 minutes.