Preheat your oven to 425°F (220°C).
Generously grease four ramekins with butter and dust them with flour.
In a double boiler or a microwave-safe bowl, combine the sliced butter and semisweet chocolate chips. Heat gently until melted and smooth, stirring occasionally.
In a separate mixing bowl, whisk together the whole eggs, egg yolks, sugar, salt, and vanilla extract until pale and frothy.
Pour the melted chocolate and butter mixture into the egg mixture, stirring continuously until well combined.
Gently fold in the all-purpose flour until just combined.
Divide the batter evenly among the prepared ramekins, filling each about 3/4 full.
Place the filled ramekins on a baking sheet and bake for 12-14 minutes.
Once baked, let them cool for about 1 minute.
Carefully invert each ramekin onto a plate and serve immediately.
