01 - Preheat oven to 425°F. Generously butter four 6 oz ramekins and dust with cocoa powder, tapping out excess.
02 - Melt chocolate and butter together in a heatproof bowl over simmering water or in 30-second intervals in the microwave, stirring until smooth. Let cool slightly.
03 - In a medium bowl, whisk whole eggs, egg yolks, and powdered sugar until pale and thick, about 2 minutes.
04 - Stir the melted chocolate mixture and vanilla extract into the egg mixture until well combined.
05 - Sift in the flour and salt, then gently fold until just incorporated without overmixing.
06 - Divide batter evenly among prepared ramekins placed on a baking sheet.
07 - Bake for 11 to 12 minutes until edges are set but centers remain soft and slightly jiggly.
08 - Let cakes rest for 1 minute. Run a thin knife around edges and invert each onto a dessert plate. Serve immediately with vanilla bean ice cream and garnish as desired.