01 - Preheat the oven to 390°F. Grease four 5 fl oz ramekins with butter and dust lightly with flour, tapping out the excess.
02 - Break the chocolate into pieces and melt with butter in a heatproof bowl set over simmering water, stirring until smooth. Remove from heat and allow to cool slightly.
03 - In a large bowl, whisk together eggs, egg yolks, and granulated sugar until pale and thickened.
04 - Gently fold the melted chocolate mixture into the egg mixture. Sift in the flour and salt, then fold 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 wobbly.
07 - Remove from oven and let stand for 1 minute. Run a knife around the edges and invert each fondant onto serving plates. Serve immediately with fresh raspberries and optional icing sugar, vanilla ice cream or whipped cream.