01 - Preheat oven to 400°F. Generously butter four 7 oz ramekins and dust with sugar, tapping out excess. Set aside.
02 - Melt chocolate and butter in a heatproof bowl over a pot of barely simmering water, stirring until smooth. Remove from heat and cool slightly.
03 - Whisk egg yolks, 3 tbsp sugar, vanilla, and salt until pale and creamy. Fold in melted chocolate mixture and flour until fully combined.
04 - Beat egg whites in a clean, dry bowl until soft peaks form. Gradually add a pinch of sugar and continue beating until stiff, glossy peaks form.
05 - Gently fold one-third of whipped egg whites into chocolate mixture to lighten. Carefully fold in remaining whites, maintaining as much air as possible.
06 - Spoon batter into prepared ramekins, smoothing tops. Run thumb around inside edge of each ramekin to help soufflés rise evenly.
07 - Bake for 16–18 minutes until well risen with slight wobble in center. Do not open oven door during baking.
08 - While soufflés bake, heat milk, cream, and vanilla bean (or extract) in saucepan over medium heat until just below simmering.
09 - Whisk egg yolks and 5 tbsp sugar until pale. Gradually pour hot milk mixture into yolks, whisking constantly to temper.
10 - Return mixture to saucepan. Cook over low heat, stirring constantly with wooden spoon until thick enough to coat back of spoon. Do not boil. Strain into bowl. Remove vanilla bean if used.
11 - Serve soufflés immediately from oven with crème anglaise poured over or alongside.