Preheat & Prep: Preheat oven to 425°F / 220°C. Generously butter four ramekins and dust with cocoa powder to ensure easy release.
Melt Chocolate & Butter : Melt butter and chocolate together in a heatproof bowl over simmering water (or microwave in 20-second bursts). Stir until smooth and glossy. Let cool slightly.
Whisk Eggs & Sugar: In a separate bowl, whisk eggs, yolks, and sugar until pale and thick : this gives your cake lift and a tender edge.
Combine & Fold: Slowly pour melted chocolate into the egg mixture, whisking constantly. Gently fold in sifted flour, salt, and any optional flavorings.
Fill Ramekins: Divide the batter evenly among ramekins, filling each about ¾ full. Place on a baking sheet for stability.
Bake: Bake for 8–10 minutes until edges are firm and centers are just set but still wobbly. Timing is critical : a few seconds make all the difference.
Rest & Serve: Let rest 45–60 seconds. Run a thin knife around the edge, invert onto a plate, and serve immediately. Dust with powdered sugar and garnish with berries or ice cream.