1. Preheat oven to 425°F (220°C). Grease four 6-ounce ramekins with butter and dust lightly with flour or cocoa powder.

2. Melt butter and chocolate together in a heatproof bowl over simmering water or in the microwave until smooth.

3. In a separate bowl, whisk eggs, egg yolks, sugar, and vanilla extract until pale and slightly thickened.

4. Slowly whisk melted chocolate mixture into the egg mixture until combined.

5. Gently fold in flour and salt until just incorporated.

6. Divide batter evenly among prepared ramekins.

7. Place ramekins on a baking sheet and bake 12–14 minutes, until edges are set but centers remain soft.

8. Allow cakes to rest 1 minute, then carefully invert onto serving plates.

9. Dust with powdered sugar and garnish with berries, whipped cream, or ice cream.

10. Serve immediately.