01 - Preheat oven to 425°F. Generously butter four 6 oz ramekins and dust them with cocoa powder, tapping out the excess.
02 - Combine chocolate and butter in a heatproof bowl set over simmering water or melt in 30-second microwave bursts, stirring until smooth. Allow to cool slightly.
03 - In a medium bowl, whisk whole eggs, egg yolks, and powdered sugar until pale and thick, approximately two minutes.
04 - Stir melted chocolate mixture and vanilla extract into the egg mixture until fully incorporated.
05 - Sift in flour and salt. Gently fold until just combined 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 - Allow cakes to rest for one minute, run a thin knife around edges, then invert each onto a dessert plate.
09 - Serve immediately with a scoop of vanilla bean ice cream. Garnish with fresh berries or mint and dust with powdered sugar if desired.