01 - Preheat oven to 425°F. Grease four 6 oz ramekins with butter and lightly dust with cocoa powder or flour, tapping out the excess.
02 - Melt the chocolate and butter together in a heatproof bowl over a pot of simmering water, stirring until smooth. Remove from heat and let cool slightly.
03 - In a separate bowl, whisk together eggs, egg yolks, and confectioners sugar until pale and thick.
04 - Gently fold the melted chocolate mixture into the egg mixture.
05 - Add the flour and salt, folding gently until just combined. Do not overmix.
06 - Divide the batter evenly among the prepared ramekins.
07 - Bake for 10-12 minutes, until the edges are set but the centers are still soft.
08 - Let cool for 1-2 minutes. Run a knife around the edges, invert onto plates, and carefully lift off ramekins.
09 - Serve immediately with a scoop of vanilla ice cream on each cake. Dust with cocoa powder or powdered sugar, and garnish with berries or mint if desired.