Preheat your oven to 200°C (390°F). Grease four ramekins with butter and dust with cocoa powder, tapping out any excess.
Chop the dark chocolate into small pieces and melt it gently in a heatproof bowl over simmering water, stirring until smooth and glossy. Remove from heat and let cool slightly.
In a separate bowl, whisk the eggs and sugar together until the mixture becomes pale, thick, and slightly fluffy—about 2 minutes. This helps incorporate air for a tender crumb.
Gradually fold the melted chocolate into the egg mixture with a spatula, mixing gently until combined and smooth. Keep the batter shiny and thick.
Sift the flour and cocoa powder into the batter. Carefully fold in until just combined, ensuring the mixture remains glossy and slightly thickened.
Divide the batter evenly among the prepared ramekins, filling each about three-quarters full. Gently tap the ramekins on the counter to remove air bubbles and level the surface.
Place the ramekins on a baking tray and bake in the preheated oven for 12 to 14 minutes. The edges should be set, and the center will still wobble slightly when shaken.
Once baked, remove the ramekins from the oven and let them rest for about 2 minutes. Run a small knife around each edge to loosen, then carefully invert onto serving plates.
Gently lift the ramekin away, revealing the cracked surface of the fondant with its warm, molten center. Serve immediately, perhaps with a dusting of cocoa powder or a scoop of vanilla ice cream.
Enjoy the contrast of the crisp exterior with the silky, flowing chocolate inside—an indulgent treat that’s perfect for satisfying any chocolate craving.
