01 - Preheat the oven to 390°F. Grease four ramekins (approximately 5 fl oz each) with butter, dust with flour, and tap out the excess.
02 - Break chocolate into pieces and melt together with butter in a heatproof bowl over simmering water. Stir until smooth, then remove from heat and allow to cool slightly.
03 - In a large bowl, whisk eggs, egg yolks, and sugar until the mixture becomes pale and thick.
04 - Gently fold the melted chocolate mixture into the egg mixture. Sift in flour and sea salt, folding until just combined to maintain airiness.
05 - Divide the batter evenly among the prepared ramekins.
06 - Bake for 10 to 12 minutes until edges are set but centers remain soft and slightly jiggly.
07 - Let the fondants rest for 1 minute. Run a knife around the edges and invert each onto a plate. Serve immediately with fresh raspberries, a dusting of icing sugar, and optional vanilla ice cream or whipped cream.