01 - Preheat oven to 425°F. Generously butter four 6 oz ramekins and dust with cocoa powder, tapping out excess powder.
02 - Melt chocolate and butter together in a heatproof bowl set over a pot of simmering water, stirring until smooth. Remove from heat and cool slightly.
03 - In a medium bowl, whisk together eggs, egg yolks, and sugar until pale and thick.
04 - Fold melted chocolate mixture into egg mixture. Add flour and salt, gently mixing until just combined.
05 - Divide batter evenly among prepared ramekins and place on a baking sheet.
06 - Bake for 11 to 13 minutes until edges are set but centers remain soft. Remove from oven and let rest 1 minute.
07 - Combine raspberries, sugar, and lemon juice in a small saucepan over medium heat. Cook until raspberries break down and mixture simmers, about 4 minutes. Press through fine mesh sieve to remove seeds. Add water to thin if needed.
08 - Run a knife around edges of cakes and invert onto plates. Spoon raspberry coulis around or over cakes. Serve immediately.