Preparation Preheat oven to 375°F. Spray eight 3/4-cup ramekins or custard cups with nonstick spray; coat ramekins or cups with sugar, tapping out excess sugar. Stir chopped chocolate and butter in large metal bowl set over saucepan of simmering water until mixtures is melted and smooth. Remove chocolate mixture from heat; cool slightly. Using electric mixer, beat egg yolks, 1/3 cup sugar, and cocoa powder in medium bowl until thick ribbons of mixture form, about 3 minutes. Gently fold into chocolate mixture. Using electric mixer with clean dry beaters, beat egg whites in medium bowl until foamy. Add lemon juice to beaten egg whites and beat until soft peaks form. Fold into chocolate mixture in 3 separate additions. Divide among prepared ramekins. DO AHEAD: Can be made 1 day ahead. Cover and refrigerate. Bake soufflés until puffed above edges but still soft in center, about 18 minutes. (Bake chilled soufflés about 20 minutes.) Serve immediately.
Preparation Preheat oven to 375°F. Spray eight 3/4-cup ramekins or custard cups with nonstick spray; coat ramekins or cups with sugar, tapping out excess sugar. Stir chopped chocolate and butter in large metal bowl set over saucepan of simmering water until mixtures is melted and smooth. Remove chocolate mixture from heat; cool slightly. Using electric mixer, beat egg yolks, 1/3 cup sugar, and cocoa powder in medium bowl until thick ribbons of mixture form, about 3 minutes. Gently fold into chocolate mixture. Using electric mixer with clean dry beaters, beat egg whites in medium bowl until foamy. Add lemon juice to beaten egg whites and beat until soft peaks form. Fold into chocolate mixture in 3 separate additions. Divide among prepared ramekins. DO AHEAD: Can be made 1 day ahead. Cover and refrigerate. Bake soufflés until puffed above edges but still soft in center, about 18 minutes. (Bake chilled soufflés about 20 minutes.) Serve immediately.