Preheat your oven to 450°F (230°C). Grease six 4-ounce ramekins generously with butter and dust with cocoa powder. Set aside.
Melt the butter and baking chocolate together in a microwave-safe bowl, using 30-second intervals and stirring after each until smooth and fully melted.
In a large mixing bowl, whisk the eggs, egg yolks, and granulated sugar until the mixture is pale and fluffy, taking about 2-3 minutes.
Combine the melted chocolate mixture, vanilla extract, and salt into the egg mixture, stirring until well mixed.
Gently fold in the flour and cocoa powder until just combined.
Evenly distribute the batter among the prepared ramekins about ¾ of the way full. Place the filled ramekins on a baking sheet.
Bake for 10-12 minutes, or until the cake edges are set but the centers remain soft.
Allow the cakes to cool in the ramekins for 1 minute. Place a small plate over each ramekin and carefully invert it to release the cake. Let the cake sit for a few seconds before removing the ramekin.
Serve each cake topped with a scoop of vanilla ice cream, a drizzle of chocolate sauce, and a dusting of powdered sugar if desired. Enjoy!